85 Mercruiser 5.7 will not turn over

[slshoe2002]

I have an 85 Crestliner Rampage running a Mercruiser 5.7 260hp. I bought the boat recently so dont have alot of history on it. So here goes.

Day 1 - took boat to the lake, ran it all day, no problems
Day 2 - wife washed boat with the plufg in it, took the boat to the lake, Started fine and ran fine for about half hr... was idling around the lake at slow speed, then when I went to dump it to full throttle the boat died and made a noise like the battery was dead. I looked and thats when I noticed the bilge was full of water. The boat runs on 2 batteries and they were both dead.
Day 3 - I went and verified one of the batteries was fried and repalced it with a new one... installed the battery, same issue when cranking I get about a hlf a turn then nothing.
Day 4 - I replaced the starter thinking maybe if it got water in it maybe it fried it since its such an old motor and I believe it has an original starter. with the starter grounded to the block and wires hooked up it cranks.

I reinstalled the starter fully and crank it and get the same exact reaction... half a turn and then nothing. It sounds again like the battery is dead.

Any and all suggestions and questions are appreciated. Ive put 350.00 into parts and am still at square one. Not to mention the top of my head is pretty sore from sitting on it while I replaced the starter! LOL

 

[Bt Doctur]

Re: 85 Mercruiser 5.7 will not turn over

del

 

[slshoe2002]

Re: 85 Mercruiser 5.7 will not turn over

del?

 

[Don S]

Re: 85 Mercruiser 5.7 will not turn over

Is all your battery cable connections clean and tight. Not with a slight twist of a wing nut with your thumb and finger, but with a wrench.

Are the cable ends in good shape? Have you tried using one battery at a time? Might want to pull the spark plugs and see if you have any water in any of the cylinders as well. See if it turns over without spark plugs.

 

[slshoe2002]

Re: 85 Mercruiser 5.7 will not turn over

Yes I did tighten everything down. I also bypassed the 2 battery switch and just have the new battery run straight to the motor in case there are any issues with the switch itself. I did not however check the plugs so I will have to do that after work today and see what I find. If there is water in the cylinders what would be the way to remove it? Thanks.

 

[Don S]

Re: 85 Mercruiser 5.7 will not turn over

If there is water in the cylinders what would be the way to remove it? Thanks.

Crank the engine over, it will blow the water out. After the water is out, a little WD-40 couldn't hurt

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[slshoe2002]

Re: 85 Mercruiser 5.7 will not turn over

Okay so here is the update. I did have water in the plugs... and actually 1 of the plugs had about 2 cups of water dump out. It will crank with no spark plugs I sprayed a touch of WD-40 in it after I blew all the water out. once everything was back together it started doing the exact same thing... half a crank and then nothing.... Grrr and I was so excited too!!!

 

[Don S]

Re: 85 Mercruiser 5.7 will not turn over

You have exhaust manifold/elbow problems. Probably the gasket between them.
Remove the elbows, and take pictures of what you find. Then clean the gaskets off the the elbow and the manifold and take pictures of the gasket surfaces. Post the pictures.

 

[slshoe2002]

Re: 85 Mercruiser 5.7 will not turn over

oh what fun for a boat ive had for a week. ill keep ya posted!

 

[slshoe2002]

Re: 85 Mercruiser 5.7 will not turn over

Another quick question. I havent had a chance to check the exhaust manifolds yet and probably wont be able to until next week. But it does bring up further questions. Say the exhaust manifold is bad, shouldnt the engine still crank when I have a new battery, good plugs, and new starter? Im trying to figure out what could possibly be robbing the boat of the engergy to try and turn over. I still get half a crank and then nothing. I even took the brand new battery out and had it checked and it checked okay. I had a 5.7 in my last boat and it ran on a single 12V battery... This couldnt be a 24V system could it? Im perplexed. Would a bad manifold keep it from turning over? and as ive said it will fully crank with no plugs in it. I believe the serial number is A44077 but I can verify when I get home if that isnt it.

 

[slshoe2002]

Re: 85 Mercruiser 5.7 will not turn over

I did check that and the cylinder had no water in it after trying to turn it over a hand full of times. im going to re-pull the plugs and crank it a couple more times and make sure there is no water. It wont turn over enough to actually pull the water up... it just doesnt have enough oompf to it. At least I dont believe.... But I am a complete novice to all of this so im sure the pro's here would know better than me!

 

[Bt Doctur]

Re: 85 Mercruiser 5.7 will not turn over

The engine clock is ticking with water in a cylinder.
Remove the lower hoses from the manifolds and let manifolds drain
Remove all spark plugs, and spin motor over to get rid of any more water
Reinstall spark plugs and fire up motor USING NO WATER HOSE for about 10 seconds to dry the cylinders
Let cool, fire again and heavily fog the motor to protect it untill it can be operated normally.

 

[Don S]

Re: 85 Mercruiser 5.7 will not turn over

Do this, remove the outdrive. 10 minute job. Put the shifter in forward, disconnect the trim rams, remove 6 nuts and pull the drive off. This will protect your impeller.

Before you destroy your engine. Take the plugs out and dry out the cylinders again. Spray a bunch of WD-40 in the cylinder and crank the engine over a dozen times or so to help dry things out. Dry off the spark plugs and put them back in and see if the engine will start. Probably won't because of moisture buildup on the plugs. Pull them out and repeat this process until the engine starts. Then let it run for 10 to 15 seconds WITHOUT WATER hooked to the engine, in order to clear all the water out of the cylinders.

NOW, it's time to check the manifolds and elbows.

 

[slshoe2002]

Re: 85 Mercruiser 5.7 will not turn over

Sounds like a plan. I may not have cranked it enough with the plugs out to remove all water... looked dryish to me... but this is a first so working through the pain. one head stand in the back of the boat at a time! thanks again for the advice

 

[Bt Doctur]

Re: 85 Mercruiser 5.7 will not turn over

Thanks for catching that Don, I left out the part of letting the manifold hoses just hang down.

 

[Don S]

Re: 85 Mercruiser 5.7 will not turn over

Thanks for catching that Don, I left out the part of letting the manifold hoses just hang down.

I see we posted at exactly the same time.
Removing the hoses or the drive will accomplish the same thing. Save the pump. Pulling the drive just keeps the bilge dry.

 

[slshoe2002]

Re: 85 Mercruiser 5.7 will not turn over

Thanks for the advice!!! I got the boat started. What was robbing the motor of the power to start it from the battery was a faulty switch for multiple battery hook ups. I cleared the plugs of water removed all water from engine and after finding the faulty switch it started right up. let it run for 10 seconds. hooked everything back up. started it let it run for about 10-15 minutes on the muffs. let it sit for an hour. repeated let it it... then removed the plugs again... and no water. I dont think I have a manifold issue after all. I think the water got in there from my girlfriend washing the boat and the drain plug being in and sloshing around when on the lake. I also found one baffle on one of the exhaust pipes has been chewed through. I also found all tilt and trim wiring to be brittle and just fall apart so I figure I better replace it. Does anybody know what guage wiring should be used and if it should be stranded or solid? Thanks again everyone.