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40 hp won't start

K

keithm

Contributing Member
This is a 1991 model 0d035693. The lower unit was leaking, I found the plastic retaining ring had broken so I rebuilt the entire bottom end, seals bearings waterpump the whole thing. Also noted a water leak under the gasket just under the head cover plate, replaced that, noted a leak in the lower carb, found a hole in the float bowl replaced it. After all this, fresh fuel. It won't start. It does have a spark, it has 130lbs compression, I installed new plugs, and tried again it would hit once in awhile but not run, when I pulled the plugs they were dry, I reinstalled and then proceeded to choke the carbs, again it would hit but no start. That would normally be a sign of a broken reed, but this motor doesn't have reeds. There is a solenoid on the port side of the motor but I do know what it's purpose is. Does anybody have any idea?
next question. Why doesn't this motor have a choke? Is that the purpose of the solenoid?
 
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That's not it mine is a 4 cylinder 2 stroke. I thought all marine 2 stroke were reed valve engines. Piston port not practical in marine applications. If you pull up that serial no, you'll see what I'm looking at. I am unable to find a reed anywhere in the fiche.
 
So are you 100% sure there are no reeds in this motor ????-Have you looked at the parts break down of the crankshaft ?
 
I've heard of valve type main bearing reeds, didn't know anybody actually produced it. I'll check it out in the morning. Pain in the ... To service. So can you replace just the reeds or do you have to replace the whole bearing?
 
Mercury used internal bearing / reed blocks from the early 1950's to the 1990's on many different inline motors !!!!!
 
I assume the power head has to come off to access all this. Sounds interesting.
I ve built a number of 2 strokes over the years but never marine. It's like starting from ground zero. So far I've discovered the laws of physics don't apply to marine. Lol. Thank for the direction, I'll let you know what I discover with the sea foam tests
 
Before you go through all that, try shooting some ether in the carbs (butterflies open). You might just have a dried out interior. Seen that lots of times.

Jeff
 
Tried the ether and the sea foam, I did get it to hit fairly regularly. But would run, I thought of something I thought I'd ask about. The first thing I noticed is there is no voltage to the choke solenoid, I did jump voltage to the yellow black wire and the solenoid did open. Next I noticed that little alarm glitches when turning the key or giggling the switch. I've had a few bikes over the years that would crank and start and then die as soon as you release the button.
has anyone seen this happen in marines. I was looking for a continuity diagram for the switch to trace the circuits, but have been unable to find it. Does anyone know where I can find one?
 
Found the problem, the black/yellow wire(kill wire) was sorted to ground in the switch. I cut the wire to open the circuit and the engine runs great. So I raced the ignition switch and it works great. Dang I went around that mountain a lot. Thanks for the advice and suggestions guys.
 
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