GM Marine Engine wont start

[Gito]

GM Marine Engine wont start.

Friend has a boat with a GM Marine Engine that wont start.
He sent me a video to help him figure it out but all I could think of was that maybe its the battery or some short.
My friend told me that his boat had been sitting around for more than a year due to rain flooding the inside of the boat and temporarily submerging the engine for a day.

Does anyone on the forum recognize these symptoms.
https://www.youtube.com/watch?v=Z5DUyNxBhXE&feature=youtu.be

I can provide the year and engine size tomorrow

Any advice is greatly appreciated

 

[Colt45ws]

The engine was submerged? Was any maintenance done to the engine immediately after or was it left to sit?

 

[SnowDrifter]

From the video: Charge/replace the battery and inspect connections, including the ground

Additional from the info provided:

Do an oil change
Pull the plugs, inspect the cylinders for corrosion, purge water if needed
Replace the distributor/cap/wires
Flush fuel system w/ fresh fuel

 

[clinebarger]

GM/Mercruiser has made a TON of marine engines?

Does it have a Breaker Point Ignition?
Carburetor?
Fuel pressure?
How long has been sitting?

 

[Gito]

Originally Posted by Colt45ws
The engine was submerged? Was any maintenance done to the engine immediately after or was it left to sit?


My friend told me that he forgot to remove some sort of drain cover/plug the night it rained. Next day he discovered the engine submerged in water and the only thing he did was to drain the water by removing drain plug/cover. He was too scared to try to start the engine because he thought for sure that he would toast some wires or cause a short. He left the engine to dry out for months and then finally trying to start the engine today.

He just replaced the starter and says the batteries (2) are good.
I think its the batterie(s) that are not giving enough juice to starter but its just a guess.

 

[Colt45ws]

Originally Posted by SnowDrifter
From the video: Charge/replace the battery and inspect connections, including the ground

Additional from the info provided:

Do an oil change
Pull the plugs, inspect the cylinders for corrosion, purge water if needed
Replace the distributor/cap/wires
Flush fuel system w/ fresh fuel


Basically this. If nothing was done to the engine after it was submerged then it may have had water inside, and that water would have corroded it.
I would also add, if there is corrosion in the cyinders, then spraying some oil inside them and manually turning the engine off the crank bolt may help free it up enough to start, but it'll chug oil until its rebuilt.

 

[Gito]

Originally Posted by clinebarger
GM/Mercruiser has made a TON of marine engines?

Does it have a Breaker Point Ignition?
Carburetor?
Fuel pressure?
How long has been sitting?



I will get an answer to these questions tomorrow.

 

[clinebarger]

Now that I watched the video....Battery voltage/connection/state of charge/starter. It seems the starter solenoid was kicking in & out rapidly.

 

[Chris142]

Originally Posted by Gito
Originally Posted by Colt45ws
The engine was submerged? Was any maintenance done to the engine immediately after or was it left to sit?


My friend told me that he forgot to remove some sort of drain cover/plug the night it rained. Next day he discovered the engine submerged in water and the only thing he did was to drain the water by removing drain plug/cover. He was too scared to try to start the engine because he thought for sure that he would toast some wires or cause a short. He left the engine to dry out for months and then finally trying to start the engine today.

He just replaced the starter and says the batteries (2) are good.
I think its the batterie(s) that are not giving enough juice to starter but its just a guess.

If he let water sit in the cylinders for months then the cylinders are rusted solid. It's JUNK!

 

[NYEngineer]

Originally Posted by Chris142
Originally Posted by Gito
Originally Posted by Colt45ws
The engine was submerged? Was any maintenance done to the engine immediately after or was it left to sit?


My friend told me that he forgot to remove some sort of drain cover/plug the night it rained. Next day he discovered the engine submerged in water and the only thing he did was to drain the water by removing drain plug/cover. He was too scared to try to start the engine because he thought for sure that he would toast some wires or cause a short. He left the engine to dry out for months and then finally trying to start the engine today.

He just replaced the starter and says the batteries (2) are good.
I think its the batterie(s) that are not giving enough juice to starter but its just a guess.

If he let water sit in the cylinders for months then the cylinders are rusted solid. It's JUNK!



Yep. Water gets into the cylinders through open exhaust valves and that's that. You need to get them started THE DAY they come up or it's game over. Time for a new engine.

 

[Schmoe]

Also, how does he know the starter is good? Sounds like it's either low battery or starter. Engine is slowly moving. Personally, if you are sure about the battery and starter, I'd pop the plugs, and then get a ratchet and see if I can get the engine to turn over without the starter. If it does, then start it with the plugs out. Should be easy enough without compression. Another thing, check the dipstick. If water got into the engine, that oil will be milky looking.

 

[Trav]

The first thing I would do is pull the plugs and use a small boroscope to look in the cylinders, if they show signs of rust its not a good situation for him.
Until you know exactly what he is dealing with its all guessing.

 

[Gito]

Spoke to my friend this morning and the following has been checked or replaced;

Cylinders have no water or evidence of water.

Crank shaft turned with breaker bar and no issues there.

Spark plugs replaced

Carburator looks good

Fuel filter replaced

New starter (old starter was giving one click sound each time the ignition was turned)

Batteries are not New but thinks that they should be good.

 

[OVERKILL]

Has he put a battery charger on it? Tried boosting it?

 

[StevieC]

Does this engine have an external starter solenoid that supplies power from the battery to the starter triggered by the key? Is it defective and/or wet from the flood?

You can try jumping using a booster cable from the battery positive terminal to the starter terminal with the key in the on position and see if it starts that way. If it does look at the external starter solenoid and/or the wires to the solenoid / starter.

 

[jeepman3071]

Originally Posted by StevieC
Does this engine have an external starter solenoid that supplies power from the battery to the starter triggered by the key? Is it defective and/or wet from the flood?

You can try jumping using a booster cable from the battery positive terminal to the starter terminal with the key in the on position and see if it starts that way. If it does look at the external starter solenoid and/or the wires to the solenoid / starter.


This. I also think it might have something to do with the starter being flooded.

 

[mk378]

Measure voltage at the starter while trying to start. If it is OK, likely a bad starter. If no good, measure at the battery, if that is dropping it is a run down or faulty battery. If OK at battery but not the starter, check the power and ground wires. Measure voltage drop along each path, again while trying to start.

 

[DoubleWasp]

Circuits:

The thing that people forget when a boat is flooded is that all power carrying circuits begin super corroding immediately. Sometimes they even fizz like an Alka Seltzer tablet. I'd bet anything that he has a solid case of "green wire" syndrome at this point.

Batteries:

Forget the charger. Forget their age. If they can't pass a load test and demonstrate sufficient cranking amps, then assume nothing about the batteries.

Get some KNOWN GOOD or NEW batteries and stop BeeSing around with those likely-bad batteries. 20% of my business is stuff that gets solved simply by replacing weak batteries.

What to do now:

Forget the boat's electrical system. Hook a new battery directly to the starter stud with a good new 4 gauge cable (minimum ), and the negative directly to the engine block (grounding studs are at the rear of the engine on back of the bellhousing on both sides) using a new 4 gauge cable. You can get the battery and both cables from advance for cheap.

WHEN the engine starts (I have no doubt it will), then you can begin your diagnostic process.

Hook the good new battery to the factory cables. See if it starts normal. If it doesn't, do this:

Hook back the factory wiring. You can use a rat toaster battery load tester for the next part. Ground the negative of the rat toaster to the battery negative. Use he positive clamp of the toaster to test amperage at the battery, battery switch, and at the starter stud. Wherever the cranking amperage drops off, your problem cable is upstream of that point.

Forget voltage. I have a whole pallet of batteries with perfect voltage that couldn't start a conversation, and a whole box of cables that can carry perfect voltage but can't carry 100 cranking amps.

Cliff's notes:

1. Eliminate the engine as a culprit by using external battery and cables.

2. If engine is not the problem, find your bad connection by load testing everything down the power circuit.

Trust me. I do this literally every day.

 

[Donald]

He needs to bring it to a marine mechanic. There are lots of things that need to be checked. The alternator, trim pump, trim tab pump if equipped.

Did the water level cover the carb and flow into the engine through the intake manifold?

If the plugs are out, the engine should turn over pretty easily.

The cylinder wall could have lots of rust around each ring. Squirt some oil or MMO down each cylinder.

 

[DoubleWasp]

Water wouldn't get that high in that boat. Once it gets hogh enough to emerge over the lip of the engine bay, it has to spread over the entire deck of the boat before making vertical progress.

He's already checked the cylinders. Clean and dry he says. He can evaluate trim pumps by popping the caps and seeing if the fluids turned to milkshake.