1992 merc 40 4 cylinder acts like vapor lock

[goldstem]

the motor starts fine and will accelerate and run strong until... I shut it down and restart it a few minutes later. it will restart but will stall if I accelerate. I need to keep hitting the choke (enricher). once I can get it going at speed by bumping the choke it will then run fine again - idle, accelerate etc just fine.
the fuel bulb is hard when I do this, squeezing has no effect.
any ideas?

 

[Mike722]

Re: 1992 merc 40 4 cylinder acts like vapor lock

Does it sound like the engine is getting spark when you try to restart? I had a 1994 40hp that did the same thing. After 2 weeks the motor would not start at all. The stator was bad. Replaced the stator and the engine runs and starts great.

I assume the low idle circuit was going bad, causing the hard starting due to the heat build up after running.
I had the local mechanic test the system and then replaced the stator myself.

If you have a way to test spark when it acts up, you can determine if it is a fuel or electrical problem.

Hoep this helps
Mike

 

[goldstem]

Re: 1992 merc 40 4 cylinder acts like vapor lock

I believe spark is fine. and wouldn't think spark would be helped by hitting the choke. how is it the idle circuit is going 'bad' when once it is going, it idles just fine?

Does it sound like the engine is getting spark when you try to restart? I had a 1994 40hp that did the same thing. After 2 weeks the motor would not start at all. The stator was bad. Replaced the stator and the engine runs and starts great.

I assume the low idle circuit was going bad, causing the hard starting due to the heat build up after running.
I had the local mechanic test the system and then replaced the stator myself.

If you have a way to test spark when it acts up, you can determine if it is a fuel or electrical problem.

Hoep this helps
Mike

 

[Mike722]

Re: 1992 merc 40 4 cylinder acts like vapor lock

My engine had the older black stator that run different windings for high and low idle. The red stators used one set of windings. I thought mine was a fuel problem until it quit all together.

I do not know if yours is going bad, just something to think about. If it is a fuel problem, I would look at the fuel pump or cleaning the carbs. Vapor lock is possible, but if the motor run fine before there would have to be an increase in heat at the engine for some reason.

Mike

Mike