Unlimited jd

Water leaking into the cylinder causing a misfire, possibly enough to stall it if the idle is low and enough water gets in.

Drew555

Thank you

Brandonb_05

Its probably is a carb problem, definitely a good start. In your original post you asked if you should check anything else. Timing is just a suggestion and a easy check. Good luck I hope it's a easy fix for you. One other thing is if you put new plugs in did you check gap?

Brandonb_05

Oh yea the manifold, I was slow, didn't see that part

Ta12sec

Plugs are gapped, the manifold is an external leak but who knows what the inside looks like. Boat spent it's first 28 years on fresh water, be intrested to see what's inside.

Brandonb_05

Let us know what you find.

FIXX

[QUOTE=33outlawsst;4253734]Did I miss something or did the OP say it only happens when its HOT, Im not a carb guy but it sounds like its trying to Vap the gas in the bowl, starboard engines being Carb or EFI seem to have issues in hot & high humidity days in a lot of cases[/QU,

might be running good with the choke half on then when it fully opens it will die..

BUP

Have to throw this out. what year is your engines, I see you have a hull of 1985 but that means nothing as far as engine(s)l model years, is your carbs 2 bbl or 4 bbl. Is your engines and carbs all stock ? do you have Thunderbolt IV ignition or Thunderbolt V ignition stock Mercruiser set up - this is all depending year model of engines..

May be easier to ask whats not stock on your engine set up ? Is the choke on the carb working properly I would check that first of all ? do you have your carb properly adjusted and your rpms set correctly in the water in fwd gear. Have you check your fuel pressure ? have you changed all fuel filters ? When your engine is about to stall, spray carb cleaner down the carb and see if engine picks back up, if it the engine does pick back up, then its is starving of fuel - carb overhaul & correct carb adjustments needed and or possible fuel restriction in the system could be a problem as well,

if the engine dies with carb cleaner down the carb, then possible to much fuel but still possible carb overhaul & and or carb adjustments.. Do this a couple of times with the carb cleaner down the carb to verify the same results happening. If your engines are before 1996 year models, you should have a mechanical fuel pumps after that year should be electric - maybe give or take a year.. Also what did your spark plugs look like ? - Any rust ,or water, or oil fouled, or gas and so on them - what color were they when you looked at them?

Ta12sec

Well it runs.... Went down last weekend and changed the exhaust manifold, no internal leaks looked ok for a raw water cooled manfold. Went to start it and it wouldn't fire, cranked and cranked sputter twice but no real fire. Ran the battery down trying to get it to fire. No big deal put the muffs on the other engine fire it up and use the alternator to charge the battery. Went back to playing with the non running motor and all of sudden smell melting plastic, slam the engine cover and no water coming out the pipes, some one in the yard must have tripped on the hose and pulled the muffs back an inch.... An inch away from the water pickup. Called it a day and spent the week planning a course of action. New qjet from jet performance 320.00 shipped to my door, can't beat that . and another new coil I had for the other motor. it. Rebuilt the water pump and housng for the port motor and then Installed everything to the starboard motor, and still no fire. Check for spark, spark is good. Have the wife crank while I watch the timing light. I can't even see the timing mark when the light goes off. Turn the advance on the timing light up to 30 and crank again I can barly see the timing mark. Loosen the distributor, spin it an inch and half, turn the key and she fired right up. Set he timing to 8 and adjusted the new carb and she idles nice at 650 and sounds good free revving it. No idea how timing ended up so far out. The distributor was tight no signs of it moving but it is what it is. Checked the other motor and timing was perfect. No idea but hoping I can finally take the thing out. Tomorrow

Drew555

Take it out tomorrow hahaaaa! Where I live it is 7* outside........7*........ It's f%#* ing cold. And Im still waiting for my block to come back from machine shop.