Repowering with a Tractor Motor

Janice:


You do have a sense of humor and a thick skin.


Following up on Ski's thoughts, if you bolt up the mixer that you referenced above, it will probably not have enough height to flow downhill to the lift muffler.


Buy the one that I referenced for $155. Get your welder friend to cut off the round tube that goes to the "contraption" and weld a 2" SS coupling to it. Then add an elbow to turn up and another nipple to go up as high as you can in that engine compartment before you screw on the Yanmar mixer. Then route the outlet to your lift muffler with 2" hose.


You will need to support it so all of the weight doesn't hang off of the exhaust manifold. Get your welder to make up a strut out of 2" angle. Bolt the bottom to one of the starboard side transmission bolts and bolt the top end to a tab welded on the elbow.


Then insulate all of the exhaust manifold and the 2" pipe nipple and elbow up to the mixer. You can use the heat shield tape here- JEGS Performance Products 32030, JEGS Heat Shield Tape | JEGS Performance Products and wind it around each element.


The whole thing will cost $155 for the mixer, $50 for a couple of SS elbows and nipples, $20 for insulating tape and will take one cut and one weld.


Spend the money, do it right and you won't regret it.


David

Re Janice's coment re shaking and Ski's #4 the "exchanger" may survive the vibration as there will be little .. on the engine. But the boat will vibrate a lot at low rpm's.
Yes I'm one of the guilty ones that wish we could start this all over again.
One saving note is that all can be changed out after launch. Janice the important thing about the pump is that it has a vane type RUBBER impeller. And the volume needs to be quite close to optimal. That's why I mentioned my pump that is only a tad bigger than what you need. I think that will fly by Ski and hope he concurs.
I'm sure you will get the normal exhaust elbow in time.
It sounds like the mounts are way too stiff but that will only be a vibration of the boat problem. Later some day you can Address that one. Shaft alignment will be easier though. Be advised that prop shaft will need to be done again once you're in the water. Do that basically ASAP.
If it were me I'd be beating the bush hard for a water cooled exhaust manifold. e-bay, Craig's List ect ect. Find out what marine engines use that Kabouta engine (think sailboats or aux. generators).
For all those that have given advice too late or too supportive of the out of the box stuff think what Janice's world would have been without our input at all.

IIRC, the aformentioned hydraulic pump was accompanied by a pic of said hydraulic pump. The pic was in fact of a hydraulic pump. And yes PS, I think much has been lost in translation. The later pics show a fairly nice installation. The raw water pump is about 3 times to big, but thats better than to small. I would experiment with larger pullies until the flow was right. Lower pump rpm equates to longer lasting impellors. It wont take much water thru that big HX to get sufficient cooling. On the HX, again, way overkill but to much here is a good thing, and no it wont "overcool". I agree that the quest for a true marine exhaust manifold and mixing elbow should be on the short list. 86 that SS box. Definitely get a decent alternator.

Ski in NC said:

3. Alternator is tractor type and only makes maybe 10A. If you want good batt charging, need to upgrade to a car type alternator.

Click to expand...

I've got a Hirth (spelling?) 60 amp from a friend's Yanmar. He upgraded to a Balmar120 and passed along his old one. And the old alternator is in a box. New one has a different footprint (of course -- it is a boat)

J

I did send a PM (private message) Ski. And thank you a lot for your patience in dealing with someone who is way out of her league as far as engines goes. But I didn't have to say that, did I?!?

kulas44 said:

The raw water pump is about 3 times to big, but thats better than to small. I would experiment with larger pullies until the flow was right. Lower pump rpm equates to longer lasting impellors. It wont take much water thru that big HX to get sufficient cooling. On the HX, again, way overkill but to much here is a good thing, and no it wont "overcool". I agree that the quest for a true marine exhaust manifold and mixing elbow should be on the short list. 86 that SS box. Definitely get a decent alternator.

Click to expand...

It's a Jabsco raw water pump kulas44... and it is big. The mechanic consulted a catalog and said it was a Jabsco F5B8007 with 1" ports. Variable pulley driven. V-belt.

So I came down to the boat and checked. The numbers on the pump that are visible read 6523-8000

A friend passed along his Hirth60 amp alternator so that's covered...

I'll be glad when this nightmare is over. This has not been much fun.

And Seaweed... well, she's my home. My heart and soul are in this haven. I'll be glad when the motor is running. That will no doubt make this part fade from my memory faster than a pelican arrives at the pier when a fishing boat comes to the dock.

BEWARE , When the engine operates it sometimes is done that the boat tied in its slip the engine is run up.

Fine for FWD and Rev check at idle , but after that any power check should be underway.

Your prop is designed to be fed water at perhaps 5K at cruise speed., the boats speed.

The pitch will add 5K+ to the water flow so the props output will be about 10K, this normal.

The problem is stationary the prop will attempt to pump the water to 10K , with N0 fwd motion.

With an efficient large diameter prop you can easily overload the engine.

Black smoke will usually occur and you might think something is wrong , when its not.

You also will have to install a gate valve in the sea water circuit as an engine that size would require what a 3/8 or at max a 1/2 inch pump would output.

If you overload the muffler /exhaust with water it can back up into the engine , a big NO NO.

Look at what the marinizers for this model engine chose and install that size!! Look at Beta Marine

Some times bigger is not better.

The 1 inch can be returned new .

"Bigger is not better"?

Did I hear you say that FF?

I never woulda thunk.

"Bigger is not better"?

I did say SOMETIMES!

How does yet another million gov, burorats sound?

FF is right. That 1" pump has worried me too.


That much pump will try to push more water through the mixer and it may be more than the water lift muffler can exhaust effectively. And I doubt if a valve in the circuit before the exchanger will work well either. It will cause the pump discharge pressure to skyrocket, produce lower flow than design and probably will cause premature impeller wear.


Replace that pump with at most a 1/2" pump as FF suggests.


David

As a single data point, the standard size raw water pump on a Ford Lehman 120 is 3/4". When we went with new Johnson pumps on our engines we installed 1" pumps on the recommendation of American Diesel and our diesel shop. This noticeably increased the flow which did not change the engine coolant temperature because of the thermostat but did lower the transmission temperature some, which is good.

When it comes to pump pressures and muffler capability and so forth I'm pretty ignorant. But I wonder if the flow from a 1" pump on a tiny engine could prevent the engine from reaching its proper operating temperature except at high or maximum rpm?

Marin,
Not if the thermostat was functional.

It wont affect engine temp. It will overload the exhaust. The HX is large enough to handle the flow but if she dumps all of the water into the exhaust it will compete with the exhaust gas for available space, the water will win. Bad juju for engine. A gate valve after the HX and befor the muffler is the fix, just like on most older sporties, just adjust the valve until you get the flow out of the exhaust that you want. Again, not rocket science. I would lower the rpm of the pump with a bigger pulley. Does Janice not have "the book", Boat Owners Mechanical and Electrical etc. or the other must have mechanical systems book (drawing a blank) by ???.

manyboats said:

Marin,
Not if the thermostat was functional.

Click to expand...

Yes, I guess I answered my own question in my own post, didn't I?. Thanks.

Marin:


Putting more raw water through the engine's heat exchanger is analogous to driving a car fast and getting more air flow over the radiator. No harm because it is the thermostat on the engine's cooling system that regulates engine temperature. Once you get enough flow to carry away the heat, more doesn't help or hurt.


As you note some engines have other heat exchangers with raw water feeding them that are not regulated such as the transmission in your boat. Those will get cooler with more flow. But that little Kubota doesn't have these.


And to put it in perspective your 5.8 liter engine needs a 1" pump. I am suggesting a 1/2" pump for the little Kubota which should produce 1/4 the flow of a 1". The Kubota engine is about 0.7 liters, so it sounds a bit big at 1/4 the flow for 1/8 the liters. The pump also needs to be matched to the mixer and I think that the Yanmar mixer that I referenced uses a 1/2" pump.


The basic requirement for a raw water pump is to put enough water through the heat exchanger to carry away the heat at wot and completely fill the spray nozzle holes in the mixer at idle so you get a good spray pattern. Any more is wasted although most engines I suspect have twice the flow required to meet these criteria to allow for marine growth and busted impeller vanes.


But you realize, all of this interesting technical discussion is probably wasted.


David

Driving the car faster to get more air to cool better only works to a point of diminishing returns. Eventually the speed requires more power generation (heat) than the radiator can suplant, regardless of airflow. Oh, I think I left a window open, I'm feeling a drift

A little birdie told me it might be just easier to do a T-bypass for excess pump flow...pretty common on genset installs was the reference point...


here is the comment...


"As far as the exhaust system is concerned, simply teeing off a bypass valve before the mixer or spray ring will assure proper performance of the mixer and the lift muffler. That is a common means to regulate exhaust water flow to control backpressure and prevent flooding the lift muffler or water separator. We do that all the time. It is far far more practical than trying to calculate pulley size or pump capacity."


To be fair....without more explanation or taken too much out of context might not answer all possibilities...but this sounds like a simple, realistic approach too.

Yes a bypass would work, but it depends on the skill of the operator to adjust it right and keep it that way ;-).


David

And guessing the heat removal and exchanger size is just as much as a gamble without the designer specs.

kulas44 said:

It wont affect engine temp. It will overload the exhaust. The HX is large enough to handle the flow but if she dumps all of the water into the exhaust it will compete with the exhaust gas for available space, the water will win. Bad juju for engine. A gate valve after the HX and befor the muffler is the fix, just like on most older sporties, just adjust the valve until you get the flow out of the exhaust that you want. Again, not rocket science. I would lower the rpm of the pump with a bigger pulley. Does Janice not have "the book", Boat Owners Mechanical and Electrical etc. or the other must have mechanical systems book (drawing a blank) by ???.

Click to expand...

Mechanic had discussed a gate value and adjusting the speed of water flow with same.

Of course I have Calder's. And it's well thumbed. I even recall the first day I could put the thing away -- nothing to fix!!! -- and how I made phone calls to friends afloat.

I did not confess why I was so chipper. Putting away Calder's was the cause. I think I even wrote about it in the Log Book.

Another question came up... A good friend of mine has a classic Hatteras. He swears that the reason his Detroit diesels are still running well is because after each run he flushes the cooling system with fresh water. It's a raw water boat.

Would something like that abate the potential damages from salt water in that SS box of mine? Simply at the end of the day run the motor sucking fresh water for five minutes to replace the salt water...

Is that something that in your view would help?

And thanks for your patience. I'm getting out Calder's now. Third Edition.

P.S.- I know the exhaust elbow is the Ideal Solution. I'm wondering if what I have can be used in the interim successfully for a longer duration with a fresh water flush.

Ditto the elbow. My friend in St. Pete says that's the first thing I should do once I'm there.

I won't have that done here (Job scope creep)
But soon? It sure does sound like a Good Idea to me.

Good question Janet,
I can't remember .. is the seawater pump issue solved? Has it got a rubber impeller? With that problem solved you can run the engine. Lots of vibration and heat but if the "heat exchanger" dosn't fall off or come apart you should be able to limp along. How long and how far is a very open question.
I don't see what the flushing has to do w it unless you're thinking of running the engine w seawater circulated by the engines coolant pump .. How would you prime it? Could work if the engine was below the WL. It's at least questionable if the engines water pump would be able to pump through all the additional places like the exhaust and the seawater intake. Is that what you're thinking?

Don't use a gate valve to throttle fluids. The gate rattles in the seats until something (the stem or gate, usually) breaks.

Use a globe valve or ball valve.

Of course throttling the suction or discharge of a positive displacement pump is not a great idea anyways.

Yes, you have an over sized pump. Consider a pump return loop or outlet branch to another discharge.

Yes, you have too large of a heat exchanger. Bypass or plug tubes.

Yes you have a 2 bolt flange on the manifold inlet. Might need to play with different gaskets or seal externally.

Yes, schedule 40 316 pipe will not provide great heat transfer to the exhaust going through it. The "manifold" is, ahem, unusual

Yes, the "manifold" might chloride stress corrosion crack. Might. Might not.

Yes, the U bend of the pipe seems shallow. Use an injection nozzle to direct raw water inlet downwards.

Yes, the pretty welds are on the outside of the box, instead if on the inside, where they need to be.

But. I think you just need to finish it off and run it. It will either fail quickly, or it may just work. Hopefully long enough to go somewhere else. Monitor and fix everything later. As Voltaire said, the best is the enemy of the good.

It may not be engineered (it is not), but you aren't going to know how well or poorly it is going to work unless you run it.

janice142 said:

There is no shop manual that I can find for the Kubota 720-40. I've looked. Once I find something that will suffice, I'll buy it or have it printed if it's a digital version. I need paper versus screen time when studying something like this.

Click to expand...

Janet - Your engine (less the marinized bits) is the same as the Beta 20.

You can find a manual for them here:
Beta 20 - Beta Marine

Inserted below, in bold text.

manyboats said:

Good question Janet,
I can't remember .. is the seawater pump issue solved? Has it got a rubber impeller? With that problem solved you can run the engine.

I asked about that and was told it's a Jabsco. (variable pulley)
Also, the numbers on the top say 6523-8000

Picture here:

Lots of vibration and heat but if the "heat exchanger" dosn't fall off or come apart you should be able to limp along. How long and how far is a very open question.

There is a cradle built for the heat exchanger. It's already mounted to the forward bulkhead in the engine room. It is above both the manifold and the Vernier lift water muffler.

This is a much smaller one than I had on the Beast. Then I had two large Centek tube-types.

Pictures will be forthcoming however since the new $130 A/C unit is due in tomorrow I'm waiting until then before bilge diving...

I don't see what the flushing has to do w it unless you're thinking of running the engine w seawater circulated by the engines coolant pump ..

No salt water will ever enter Betsy. The whole complication with this manifold system was as a direct result of making sure that salt water won't get into my motor. She'll have a closed system with the coolant running from the heat exchanger, through the manifold then back through the engine. Repeat.

Raw water (salt) will come in at the sea strainer and flow through the heat exchanger. From there, some will be injected into the pipe just prior to it exiting the stainless manifold. That (theoretically) will cool the pipe enough that the hose (runs from there to the water lift muffler) will be undamaged.

Here, I've read that too much water is either a bad thing or nothing to worry about. The boys in Carrabelle had talked about adjusting the water flow for when I'm running.

I specifically asked if this was something I would have to mess with when underway. It was stated that once the adjustment was made it was "lifetime" and I would not have to touch it again.

There was much discussion here (Carrabelle) about the merits of a radiator, fans and more. A dry exhaust too came into the arguments. Ditto Keel Cooler though I was not in favor of a keel cooler.

I've been known to test the depth with my skeg. And too, I just don't like 'em. Ditto the dry exhaust. Here, in the south that won't work on a boat as small as Seaweed.

How would you prime it? Could work if the engine was below the WL. It's at least questionable if the engines water pump would be able to pump through all the additional places like the exhaust and the seawater intake. Is that what you're thinking?

Click to expand...

I must not have explained myself well. I wondered if running a gallon of fresh water through the salt side of the cooling system would abate any issues of salt and hot gasses at the exit of the SS box.

If I understood it correctly, a friend has a hose gizmo tee-d off his sea-strainer. Just prior to shutting down the engine he turns on the fresh water and shuts the thru-hull. Thus his risers(?) do not have salt water sitting in them between runs.

Since one of the parts that was brought up previously in this thread was the point of salt water at that nipple inside the SS manifold (corrosion at the weld) I wondered if fresh would abate any possible damage.

As for another comment regarding the welds outside being spectacular and those inside questionable... mechanic was there and saw inside. He states it's just as good inside as out.

Of course, as has been pointed out, there's no way to monitor that because of the nipple location being hidden. I would not know when failure was imminent.

And I don't want salt water in the engine. For now, I am hoping that they mechanic actually follows through and has the worker here this week. Hopefully on Tuesday.

Once again, thank you for all the input. I'm learning. And I will be printing this out (hint M!!!) for inclusion in my stuff about the motor. For the Kubota 720-40 (what I have) thus far I have not found a shop manual. Nor a repair manual.

I've got Calder's but am looking for the Real Deal. Even if it's a PDF, I can have it printed and bound at a UPS store. They do that stuff quite reasonably.

I've got the one from my BOB engine and will sell it on eBay at some point. Unless someone here has an MD2 and needs a shop manual. Printed on decent quality paper with a plastic cover, spiral bound it lays flat and is pretty doggone nifty.

Pictures will be coming once I'm sitting in air-conditioning...!

And thanks again.

Janice,

Do you have a drawing showing the flow of water i.e. what hoses run to where? I attempted a guess in post #142.

READY2GO said:

Do you have a drawing showing the flow of water i.e. what hoses run to where? I attempted a guess in post #142.

Click to expand...

It's pretty close to what you have... There is no hot water heater. The hoses have not been attached but as I understand it, you're correct. The hoses are next, and then the final adjustments for cooling.

From the SS box, we go downward to the Vernier water-lift muffler (to quiet the sound) then up (loop) and down (out side of boat)... the exit thru-hull is about a foot above the waterline on the starboard side.

Oh, and the support for that SS manifold has to be cut out. The pattern is in the shop. No work here on Mondays. The shop is closed.

Also my bigger alternator needs to be mounted on the engine. The little one that came with the engine has been removed.

I see hope. Thanks to AusCan, I've got a manual. It's already been sent to the printer so by the end of the week I'll have a repair manual, and associated goodies. Thanks so much to him. That will be a big help.

It included wiring diagrams and more.
There are sections on wet exhaust and dry, keel coolers and more. It looks fascinating. There are even checklists. I like my lists.

J

Oh, and I'll take pictures once it's cool. Hopefully that will be tomorrow. The UPS driver was called and if my a/c is here, he'll deliver it right to Seaweed. Yeah.

That will be mighty fine. When it's this hot I simply wilt.

My get up and go wants to do nothing. I'll tell you how bad it is: I have a stand for my kindle and don't even hold it when reading. I do reach out and tap the page advance button all by myself. Only because I don't have a way to do it automatically.

When the a/c arrives I fully intend to install it immediately. Then I'll turn it on high, grab Skipper and take my kindle to bunk. When I wake up, life will be better, or at least cooler

Hi Janice aboard Seaweed.

Shipmate I have no advice for you as your experience aboard boats far exceeds my own.

All I have to offer you is good wishes in your endeavours to motorize your beloved craft.

Fair Winds and Calm Seas. Follow your own counsel and course.

Good Luck Madam. [ with the greatest respect ].

Regards,

David.

AusCan said:

Janet - Your engine (less the marinized bits) is the same as the Beta 20.

You can find a manual for them here:
Beta 20 - Beta Marine

Click to expand...

janice142 said:

I see hope. Thanks to AusCan, I've got a manual. It's already been sent to the printer so by the end of the week I'll have a repair manual, and associated goodies. Thanks so much to him. That will be a big help.

It included wiring diagrams and more.
There are sections on wet exhaust and dry, keel coolers and more. It looks fascinating. There are even checklists. I like my lists.

Click to expand...

If that Beta 20 manual also shows the water pumps, heat exchangers, and exhaust elbows and so forth that they routinely use... it might be giving you a shopping list of parts (and part numbers) for future improvements.

-Chris

janice142 said:

Another question came up... A good friend of mine has a classic Hatteras. He swears that the reason his Detroit diesels are still running well is because after each run he flushes the cooling system with fresh water. It's a raw water boat.

Would something like that abate the potential damages from salt water in that SS box of mine? Simply at the end of the day run the motor sucking fresh water for five minutes to replace the salt water...

Is that something that in your view would help?

Click to expand...

janice142 said:

P.S.- I know the exhaust elbow is the Ideal Solution. I'm wondering if what I have can be used in the interim successfully for a longer duration with a fresh water flush.

Click to expand...

janice142 said:

I must not have explained myself well. I wondered if running a gallon of fresh water through the salt side of the cooling system would abate any issues of salt and hot gasses at the exit of the SS box.

If I understood it correctly, a friend has a hose gizmo tee-d off his sea-strainer. Just prior to shutting down the engine he turns on the fresh water and shuts the thru-hull. Thus his risers(?) do not have salt water sitting in them between runs.

Since one of the parts that was brought up previously in this thread was the point of salt water at that nipple inside the SS manifold (corrosion at the weld) I wondered if fresh would abate any possible damage.

Click to expand...

I know lots of gas guys use a fresh water flush -- sometimes, occasionally, after every run, whatever -- and I think that's primarily because their exhaust elbows (and risers and so forth, if equipped) are cast iron.

The Detroits in your bud's Hatt may be running well more because he pays beaucoup attention to his engines (witness: incessant flushing) rather than because of the flushing itself.

Still, probably can't hurt... but I'm not sure I'd say it'd extend the life of good stainless enough to be worth the time. Others here would know better...

FWIW, Groco makes a "flush adapter" that many use for easy flushing. Check their website for pics and details.

-Chris

Gate valves are used almost exclusively in this type of situation. once it has been correctly adjusted (by taking temp readings from the exhaust under max load) it is never touched again, thereby corroding into being unmovable. Its been done this way for many years, it works. A rubber impellor pump is not really a positive discharge. DO NOT plug tubes in the HX, it wont matter if its to large, it wont affect (overcool) the engine. Thermostat thingy, ya know !! Realistically, to get to where she needs to go Janice could just point the exhaust pipe straight up, run raw water thru the engine and dump it overboard and be on her way. No harm done, short term anyway.