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-   -   New to me 50, Steel full displacement, engine questions (https://www.trawlerforum.com/forums/s3/new-me-50-steel-full-displacement-engine-questions-30464.html)

waddenkruiser 02-21-2017 01:57 PM

As long as it runs - do not tinker!

Would like to add: reliable, it has to run reliable.
And here we're at the question of preventive maintenance. But which maintenance job is really necessary immediately and which one could wait another year? It depends. But no compromise on reliability - it's a question of safety.

Obie, great looking vessel, congrats!
Regarding your engine:
As long as it runs (reliable) - I wouldn't tinker, regardless the noise. So I'm with RTF.

Might be another story if you're planning a bigger refit project anyway and if you have the money handy.

FF 02-22-2017 06:31 AM

The first step with any 2 stroke Detroit Diesel is ALWAYS an oil change.

The engine requires 40wt CFII spec oil.

Too many folks dont bother to read "da Book" and will dump what is cheap at Wallmart in.

IF you keep it I would be happy to recommend a maint/rebuild DD book to get you up to speed.

BEFORE starting any 2 stroke that may have been out of service for 1/2 a year or more it is imperative that you pull the valve cover First , and be sure all the injectors move with the rack.

Otherwise it may start , scream at high RPM till the fuel or air is shut off.

Obie 02-22-2017 10:04 AM

Very good advice thank you. My plan was to do that, have block of wood ready to killl air supply, start and run with garden hose for about 10 minutes then do the oil change. If my memory serves me. The fuel flow through the injectors is like 60 gph, with most all going back to the tank. Would I use a lift pump? Do I have to have a very large filter to handle that volume, even just to fire it off?
Obie

Ski in NC 02-22-2017 10:13 AM

I've bench run a bunch of these. I use a outboard motor fuel line with squeeze bulb and a six gal jug. There is a gear pump that pumps fuel into secondary filter, then into fuel supply rail. There is a second return rail that takes fuel back to the tank. Disconnect that and route it back to your jug.

Gear pump is mounted on one end of the blower.

The secondary filter takes care of any filtering you need, provided it is in good shape.

When priming with the squeeze bulb with engine off, you are pushing through the machined clearances in the pump and fuel barely moves through. SLLLLOOOOOW, but do-able.

If you need to prime up the secondary filter, take drain plug off bottom of can and pump fuel in there, bypassing gear pump. Don't start with hose on unless you want a diesel shower.

And definitely make sure injector rails are free to move and have some provision to choke off air. Most old ones came from the factory with a trip type damper, make sure it works and you know how to trip it.

BandB 02-22-2017 03:09 PM

Quote:

Originally Posted by Obie (Post 526159)
Very good advice thank you. My plan was to do that, have block of wood ready to killl air supply, start and run with garden hose for about 10 minutes then do the oil change. If my memory serves me. The fuel flow through the injectors is like 60 gph, with most all going back to the tank. Would I use a lift pump? Do I have to have a very large filter to handle that volume, even just to fire it off?
Obie

I can't ever recommend running with a garden hose.

Nomad Willy 02-22-2017 03:36 PM

I have a 40hp engine and take off the hose from the seacock and put it into a 5 gal bucket sitting on the trans. Then get a garden hose to maintain the water level in the bucket. Easy to do (flow wise) w a 40hp engine but will probably be able to keep up on a bigger engine. A DD may require a lot of water though.

Obie 02-22-2017 03:48 PM

Yes I agree, but DD has a huge metal mas, and it would not work under any load at all, but it should be enough at idle, and of course I will be monitoring the temp, with a gauge and a inferred gauge.
Obie

If anyone thinks this is a horrible idea please chime in. Boat is on the hard, before it gets dropped in I have to know it can run.

Xsbank 02-22-2017 03:54 PM

I think it sounds like fun. As long as you have a bung for the air intake and you are not startled by the noise, which is considerable. We have a Tolly with two 6-71s in our marina and when he goes cruising you can hear him for three days until he rounds the corner by Chatham Point. What could possibly go wrong?

BandB 02-22-2017 03:57 PM

Quote:

Originally Posted by Obie (Post 526293)
Yes I agree, but DD has a huge metal mas, and it would not work under any load at all, but it should be enough at idle, and of course I will be monitoring the temp, with a gauge and a inferred gauge.
Obie

If anyone thinks this is a horrible idea please chime in. Boat is on the hard, before it gets dropped in I have to know it can run.

I already dropped in. I know others will be less conservative than me. Even just for convenience I'd rather have it in a slip so you could keep checking and trying different things and not worry about the hose. I do realize that it's possible all you'd get out of it would be a launch and haul fee.

Obie 02-22-2017 04:22 PM

Startled by the noise. I hear that! One time I was working in my engine room on another boat. There was a batterie combiner I was trying to trace out. It had an idiot light hooked to it, so you would know when the solenoid was ingaged. Some how I kicked the motor over and she fired off. Wow did I fly out of there.

Pack Mule 02-22-2017 04:30 PM

I had an old (1965) Islander 32 ft sailboat in my back yard that I was reworking. It had a westerbeke in it . I used to crank it up once a week for 7 years . I didn't know any better and I would wedge a garden hose in the thru hull and turn on the faucet . It's a wonder I never hydro locked it .

Ski in NC 02-22-2017 06:50 PM

You can run a dd 671 on the hill on a garden hose. At idle and no load, it makes very litttle heat. All you need is a garden hose feeding the sea water pump to lube the impeller and cool the wet exhaust if you have such. You could run it probably a half hour and it will still not get up to temp.

If keel cooled with dry exhaust, you need no garden hose at all.

Pack Mule 02-22-2017 07:17 PM

I forgot he is keel cooled .

Obie 02-22-2017 11:13 PM

No it's not keel cooled, that is if I ditch the 6-71 and re power. No this setup runs right out the transom. But interesting I did find 3, 3 feet long toobs welded to the inside of the hull. When I trased them out I realized they were origanly the evaporator for the 32 volt refrigeration. Wait I mean condenser, I think?

Obie 02-22-2017 11:18 PM

Was your islander 32 a flush deck. I have had 2 of them. The first one I purchased in Port Moody BC. Put a few miles on her. I am probably the only person who ever owned two of them.

fijigone 02-22-2017 11:36 PM

Do you have dry stack? I had a salt water cooled dry stack and when I left her on the hard for an extended time I removed the impeller and just had someone run the engine until it came up to operating temp. and then shut her down. At one time it was on the hard for a year. Came back put her in the water an went off with no problems. It was a DD 6-53. So with a dry stack you can run the engine for a short time as long as the impeller is out.

FF 02-24-2017 07:42 AM

The 6-71 may pump a high volume of fuel , but its RPM that gets the big volume , I doubt if you will be above idle , not at 2100 RPM.

It is 1000% easier to check the injectors first rather than use an emergency shut down flap as found on motor vehicles or a block of wood.

At higher RPM a forced shut down can suck the oil seals out of the blower , a huge PIA to have replaced.

Pack Mule 02-24-2017 10:10 AM

Quote:

Originally Posted by Obie (Post 526431)
Was your islander 32 a flush deck. I have had 2 of them. The first one I purchased in Port Moody BC. Put a few miles on her. I am probably the only person who ever owned two of them.

No mine was a Wayfarer. It came with an atomic 4 but was upgraded to a diesel.

captBrett 02-24-2017 11:29 AM

I have a 50 ft marine trader with two sp135's and doo just fine. Bigger is not always better.

Britannia 02-24-2017 12:01 PM

Here are some numbers for my Krogen 54 in calm water.

LWL 48'
Displ 80,000 lb half load
Engine JD 6068T - 225HP
Transmission 2.93:1
Prop 34x21 (3 blade)

RPM | Speed (kt) | GPH (US)
1000 | 5.0 | 1.2
1200 | 5.8 | 1.8
1400 | 6.8 | 2.5
1600 | 7.6 | 3.4
1800 | 8.3 | 5.7
2000 | 9.0 | 7.3
2200 | 9.4 | 10.7

As you can see the boat can reach hull speed with this setup (not that I'd want to!). I hope this is of use.

Richard


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