Stalls out

Fordrulz

Cadet
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Jul 15, 2018
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Hi guys! New to this forum but have a ok repair background. I'm am kind of stumped though. I have a 1997 Thompson Calee 1800 with a Mercruiser 3.0l w/ Alpha one gen 2 outdrive. At times is starts and stalls but mostly when cruising under light throttle or at WOT the engine will stall. When it does I have to pump the throttle once and it will restart but do the same thing over and over. So far I have replaced spark plugs, cap rotor and wires, installed fuel/water separator, and rebuilt the carb. Is seems as though it idle all day until you accelerate and it will cruise for a short time then stall. Removed fuel/water separator filter and drained fuel is golden in color but no water. Anyone have any ideas of advice? Any help is greatly appreciated Thanks Chris
 

zellerj

Petty Officer 2nd Class
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Dec 13, 2017
Messages
135
If it stalls like turning off the switch it is most likely an ignition issue. If it stalls with surging and stuttering, then it is a fuel issue. My bet is that it is a fuel issue - Why? because you can start it right up again. Usually a stalling because of spark issues require that the engine set for a while to allow it to cool down.

Ignition - is the rotor firmly on the post? Did you replace the coil? Does it have the proper resistance? At idle the engine is cooler so that a faulty coil is not at the temperature that causes issues. A coil issues sometimes resolves itself after it cools down.

Fuel - how clean is the gas? When you rebuilt the carb, was it dirty? The problem could be a piece of dirt in the float bowl that clogs up the jet, then after it stalls, settles back down out of the way until it happens again. At idle the turbulence in the carb bowl is not enough to get the dirt stirred up so that it can get in the way. Cleaning a carb is tricky, and sometimes a piece of dirt on your finger finds its way into the carb bowl during assembly.
 

Fordrulz

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Jul 15, 2018
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When it stalls it happens quick. At times you can try to catch it If you try to give it gas it will stutter and die. I did not replace the coil. I do not believe it is ignition. Not sure what the resistance should be. The carb was not that dirty but rebuilt it anyway. There was quite a bit of white residue in the filter on the carb.
 

Scott Danforth

Grumpy Vintage Moderator still playing with boats
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Removed fuel/water separator filter and drained fuel is golden in color but no water.

that is no longer fuel

how long has that "stuff" been in your tank?

I would drain it and replace with fresh fuel.
 

Fordrulz

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Jul 15, 2018
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Ran it out of fuel last year. Filled it up it took 18 gallons. Added a bottle of seafoam to it. Ran it down 1/4 of a tank topped it off with 7 gallons and added 1 more bottle of seafoam. Found the choke on upside down holding no pressure on choke plate I'm curious if the plate is flopping around causing the engine to flood? I will adjust it when I get a minute of daylight and recheck. Is there a spec for the choke adjustment? Also wondering if the anti siphon valve may be causing a problem I still need to check it.
 

Scott Danforth

Grumpy Vintage Moderator still playing with boats
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stop using seafoam

as for the choke, adjustment procedure is in the factory service manual.... links in the stickies

BTW zellerj it is not the coil... it is almost never the coil. as in only about 3 coils out of a million changed were actually bad.

if its idling fine until you give it some throttle, check your accelerator pump.
 

Fordrulz

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Jul 15, 2018
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Accelerator pump is new and gives a good squirt. If seafoam is no good what do you use?
 

Scott Danforth

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I simply use gas. same stuff I pump in my truck.
 

Fordrulz

Cadet
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Jul 15, 2018
Messages
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Drained fuel tank and put new fuel in. Same thing happened. I did no notice the lights cut out when this happens. Checked a little further and I think k the issue is with the ignition switch? Anyone seen one of these fail?
 

Bondo

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and I think k the issue is with the ignition switch? Anyone seen one of these fail?

Ayuh,..... Welcome Aboard,....... Ya, quite often,.... like any electrical part, it don't like water, which it sees quite often,.....
 
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