Lehman 120 compression

I don’t have the time yet to check compression or anything on my motor but am having trouble starting motor after a few hour cruise. I have 2 1050 CCA group 27 batteries for starting bank. I do not have alternator hooked up for charging but two grp 27s should be able to start a motor at least twice, lol. It seems like there is too much load on the starter.
So hopefully there is enough info to start a conversation as to the issue. Here are my questions.

1. Has anyone used a torque wrench and gotten a value as to what the lb ft of torque it should take to turn the motor?
2. How to tell if bearings might be bad without tearing down the motor?

Full load on my motor is 40-45lb ft and free spinning at 20lb ft. Is that normal, or do I just have an electric issue. New to me boat, not great shape but a decent project if motor isn’t toast. Would love some ideas/thoughts on this from all of your experiences please. Have put around 35-40 hrs on motor in past year just moving it and light cruising on holidays. Thank everyone. I’ve enjoyed reading everyone’s posts these last 8 months.

I think its a mistake to discount the possibility that the batteries are not fine. Check the obvious and most simple stuff first.

Ken

Yes it could be bad batteries, bad connections, worn out starter, bad solenoid contacts. Prove all of that stuff good before going into the engine.

So far I agree with Ken...most likely a drained or draining-while-underway battery.

Can you describe the "hard start" a little more? Your description makes it sound like it's only the second start has a hard time turning the motor over. Does it do the same thing on the first start or only the second?

Once started, does the motor run fine? Can it make WOT? Is there an unusual amount of smoke when cold, when underway, when at WOT? If so what color is it? Can you feel back pressure if you feel you open oil fill cap with your hand or your oil fill with your thumb?

Also, any reason why you don't have an alternator hooked up?

If the engine ran ok on your last cruise and you didn't flood the engine with sea water from excessive cranking, then the engine is ok.
If the batteries are ok, then the most likely problem is the starter, the solenoid or cable connections. Don't forget to check ground connections.
You can jump the solenoid using a screwdriver across the two big poles. If the starter still drags with good batteries, then it's the starter that's the problem.
And why isn't the alternator charging the starting batteries?

Whoa, slow down. You are jumping right past the simple to the more catastrophic. You did not mention what the state of health of your batteries are. Are they new? Were they fully charged? And, how would you know? You've assumed that those batteries should be able. I would start by taking the batteries to a real battery shop to be tested. Then you will know whether they are able to hold a charge. Or, put them on a charger and then use them to start the engine. Simple first, then move on to the next.

AsheL said:

I don’t have the time yet to check compression or anything on my motor but am having trouble starting motor after a few hour cruise. I have 2 1050 CCA group 27 batteries for starting bank. I do not have alternator hooked up for charging but two grp 27s should be able to start a motor at least twice, lol. It seems like there is too much load on the starter.
So hopefully there is enough info to start a conversation as to the issue. Here are my questions.

1. Has anyone used a torque wrench and gotten a value as to what the lb ft of torque it should take to turn the motor?
2. How to tell if bearings might be bad without tearing down the motor?

Full load on my motor is 40-45lb ft and free spinning at 20lb ft. Is that normal, or do I just have an electric issue. New to me boat, not great shape but a decent project if motor isn’t toast. Would love some ideas/thoughts on this from all of your experiences please. Have put around 35-40 hrs on motor in past year just moving it and light cruising on holidays. Thank everyone. I’ve enjoyed reading everyone’s posts these last 8 months.

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Greetings,
Mr./Ms. A. All of the above is good advice. The only thing I would add is hook up your alternator.

If the engine runs, and smoke isn't pouring out the exhaust, you don't have a compression problem. Barring over a stiff engine is a sign of good compression. Starting problems can result from weak battery, poor connections, or fuel air leak.

I was chasing Gremlins on my starboard Lehman engine. Since I wanted a spare starter anyway I got one. That wasn’t the problem. American Marine suggested that I install a starter solenoid. That was’t the problem. The connection at the battery looked suspect. That wasn’t it. I assumed the battery was fine because the float voltage looked normal, between 12.5 and 12.6. Well, the problem turned out to be the battery, an 8D.

Test the voltage at the battery post while cranking. It shouldn’t drop much more than a volt. If it drops down below that your battery can’t handle the load.

I installed a single new group 27 battery and she spins great! Like everyone else, check the simple stuff first.

BTW, I’m replacing my 8D with three group 24 batteries. I lose about 10% of my total amps but handling three group 24’s is easier on my back and they are cheaper too.

Batteries are failing.
You must have some charger in between uses. Suggest you charge the batteries, start the engine, run a few minutes and shut down, will it restart. If not you have your answer. If it does start a 2nd time, what other loads are on those batteries while running which can use up reserve start power.

What`s outside normal here is no alternator charging of batts. Get the alternator working and connected, see how it goes. Worry about batts then.

BruceK said:

What`s outside normal here is no alternator charging of batts. Get the alternator working and connected, see how it goes. Worry about batts then.

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+1 Diesels have very high compression; your starter is sized to handle that. Most likely failures involving compression that would affect starting would either be hydro lock, and you wouldn't be able to turn it over with a wrench, or too little compression, and it would be turning over fast but not starting.

The new-to-you boat with no alternator might have some wiring that you don't yet know about, and while running the boat you may have been using your start batteries to power some equipment you weren't aware of.

All of the of the advice about checking cables, connections, the batteries themselves is good, but correct problem 1!

Keep us posted on what you find!

I went thru a starting issue last spring with my Lehman 120.
Batteries were "due" so I changed them and it didn't help much. Still turned over slow or not at all.
Rebuilt the starter since it looked original (4000 hours on the engine) and that might have made it a little better, but still not good.
Then I went online and learned how to do a proper voltage drop test.
I was getting a 3 volt drop with the starter engaged, which is too much.
New positive and negative cables from battery to starter and all is good again.

As an aside, I do not trust automotive battery testers like the kind that have a big coil in them. Twice my diesel truck battery tested fine according to that kind of tester, and both times a new battery solved the slow turn over problem.
YMMV

Different vehicle. My near new moto battery was having difficulty starting. Took it to the battery place and they ran every test machine they had trying to show the problem.
Nothing. Bought a new identical battery from them and years later it still works fine.
The experts are shaking their heads on that one.

45 ft lb to get that motor to rotate from the crank bolt sounds about right, just based on how hard I have lean on a breaker bar to get motion.

Agree with others, sounds electrical.

Next time it is sluggish to start warm, go down there with the wrench and try it. See if it stiffer.

First and most likely suspect is the battery, second is the starter, Third possible culprit would be the wires between the two.(this includes connectors)

It is not the engine. (period)

pete

Well thats awesome news that everyone is all saying the same thing. I didnt think the motor was bad but a neighbor of mine thought that I needed to look into it.
When I bought the boat the starter was bad but I needed to move it to the marina where I live and work near. So I bought a budget one from DB Electric. Was about 100$ shipped. Im in the middle of rejuvenating the boat right now so I only go on short cruises and an overnight rarely. The starting batteries are both about a 1.5 years old but it is possible that I depleted them down to low and killed them. I went for a cruise on Christmas Day and the starter started engaging the flywheel and melted a few wires. I think I am going to rewire all of it, new starter and battery.
Alternator is not hooked up PO stated it is too powerful and shreds the belts. Im going to get an 85 amp one this spring when i do all of that.
Very little smoke on startup, oil leak from manual fuel pump , runs great really. I guess it starts first time since my house bank has an ACR to the starting bank, then just gets a rotation and a 1/2 second time if i shut down for any reason.

Greetings,
Mr. AL. Alternator too powerful? What's the rating? Should be good up to about 120 amps...100 amps for sure with a single belt. New gasket on fuel pump should cure leak. Not hard to make and/or cheap to buy.

A F.L. starter can run up to $500 plus shipping. If you shop around you can get one for around $350. A $100 started will not fill the bill, get rid of it.

The alternator story sounds bogus. Of course the engine will not start without an alternator. As an engine, any engine, gets warm the compression increases making the starter work harder.

Melting wires indicates a huge amp draw from the starter. Replace the wires and replace the starter. Hook up the alternator and stop worrying about that F.L.! Unless it has in the neighborhood of 25,000 or 30,000 hours on it look elsewhere for the starting problem.

pete

Greetings,
Mr. PM. Um, a bit of misinformation in your post IMO. ANY engine will start without an alternator. Gassers can run quite happily until the battery goes dead and can't provide ignition power. Once started (without an alternator) diesels will run until shut down. All bets are off IF the water pump is belt driven and that belt is part of the alternator loop. Both will overheat.


A warm engine usually starts much more readily as compared to a cold start.

he alternator story sounds bogus. . .

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I knew of one person who had too large (in amp hours) of an alternator and when the batteries got low it would smoke the single V belt in a few minutes. Happened a couple of times to him. (he was a slow learner)

I had my original starter rebuilt for $140. Any rebuild shop can do it, nothing special about these old school starters.

Like too rich or too thin, you can never have too much compression.

Right, I just meant that a battery becoming more tired will have a harder time cranking the engine. Depending on power draw while underway his battery could be supplying demands other than the starter.

I'll stand by my original statement on warm vs cold engine. A warm engine has higher compression than a cold engine. If it starts more easily or not is probably dependent on the particular engine/battery/starter circuit.

pete

Wonder why diesels usually have engine heaters in cold climates?....heck I think all Ford diesel trucks come factory with them and not coolers.

Maybe compression is higher, but other factors seem to be more important.

He stated it was a 140 or so. I’ve bought the double pulley for alternator but still need water pump one. Thank god the crank already is a double. Will save up for correct alternator wires and battery. Gotta redo house bank too. Fuel pump is not being used, got a low amp electric one, will do the block off plate soon also. Thanks everyone for all the advice and tips. You all are helpful as usual!!

Another cause of premature belt failure can be misalignment of the pulleys, twisting and excessively loading the belt. Worth checking.

Invest in a 100amp battery tester from HARBOUR FREIGHT , check battery then connect to starter terminal and do a discharge test there. All will be revealed. It will be the best $19.99 you ever spent.
https://www.harborfreight.com/100-amp-612v-battery-load-tester-61747.html

Martin J said:

Invest in a 100amp battery tester from HARBOUR FREIGHT , check battery then connect to starter terminal and do a discharge test there. All will be revealed. It will be the best $19.99 you ever spent.
https://www.harborfreight.com/100-amp-612v-battery-load-tester-61747.html

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I have one of those, so does RTF I think. The load test is complete when you smell smoke.

They are not the elite of testers at only 100amp. but will test the circuit as you move it down the starting circuit and show poor connections etc.

RT Firefly said:

Greetings,
Mr. PM. Um, a bit of misinformation in your post IMO. ANY engine will start without an alternator. Gassers can run quite happily until the battery goes dead and can't provide ignition power. Once started (without an alternator) diesels will run until shut down. All bets are off IF the water pump is belt driven and that belt is part of the alternator loop. Both will overheat.


A warm engine usually starts much more readily as compared to a cold start.

Click to expand...

Mostly true. Many diesels have some kind of electrical solenoid to cut off fuel. Once the battery dies the solenoid closes unless you physically wire the solenoid open. On older engines like the Lehman’s that have physical devices used to cut off fuel they will run until the run out fuel.