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OMC 23 litre dies when I slow to about 1000rpms and wont start again

S

solcat

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"My 2.3 ford in my 17' bay

"My 2.3 ford in my 17' bayliner accelerates well, with a top speed of 41mph. However, when I slow down to 1000rpms, it coughs and dies. It will not start again for a day, then it starts well, runs well at high speeds but again dies when I decelerate to 1000rpms or there abouts (just before I put it neutral). I can go slow all day tho and it runs well, starts well etc. It only dies adn wont start again when I slow down from higher speeds. Any ideas?"
 
"Had a carb kit put in. As an

"Had a carb kit put in. As another person mentioned, the spark goes right down and that is why it wont start again. I just cant figure out what is causing the spark to go right down only when I decelerate. Did the plugs, replaced the condensor, and had the points redone. Any ideas are appreciated."
 
I wonder if the timing advance

I wonder if the timing advance in the distributor (weights and springs) are rusty and stiff and possibly sticking in the advanced setting after running at high speed but slowly go back to normal when you leave it for a while? Maybe pull the points plate in the distributor and check them.
 
"my first thought was water ge

"my first thought was water getting in the cylinders. When it dies, pull all spark plugs and crank engine - see if water comes out."
 
"thanks for the replies.....ch

"thanks for the replies.....checked the distributor, seems okay....and no water in cylinders....so I am really stumped....any ideas I could try would be helpful.."
 
"not to be a smart a$$ but did

"not to be a smart a$$ but did you pull the points plate and look underneath at the weights and springs?

Next time it happens see if you can measure for 12v at the coil with the key on start, when you say it won't start I'm assuming the engine cranks over ok but it just doesn't fire?"
 
"I will take another look at t

"I will take another look at the distributor...if there is a problem with the springs and weights, what can be done about it? Yes, it turns over fine and it may cough a bit but not start. The spark looks very weak when I turn it over."
 
The weights and springs can be

The weights and springs can be replaced if that is your problem.

Was the timing checked/adjusted after the points were touched? Get a timing light and check it at idle and then rev it up to see if it advances and then does it go back down to where it should be at idle.
 
"Have you tried running with t

"Have you tried running with the ESA unplugged? faulty ESA, or even 1 of the esa switches out of whack could certainly weaken the spark
Sometimes just getting some penetrating oil in at the advance weights will free them, but as mentioned, you can't see anything of interest until the points plate is out. If the spark is weak, recheck the points while you are in there. Make sure the rubbing block is sitting right and the gap is correct.
"
 
When you go to put in gear the

When you go to put in gear the ESA makes the engine hesatate for a split second that helps the gears go together.
 
While the ESA may activate goi

While the ESA may activate going into gear it's primary role is to cause the RPM's to drop by pulsing the ground side of the coil while coming out of gear into neutral. With it unplugged expect to find it harder to go into neutral. You can help this somewhat by making sure your idle RPM's are as low as they can go without stalling the engine (around 550-550.)Remember that this is only a test and it should be plugged back in once you determine if it's the problem or not. If it is then you'll need to see if it's the unit itself or the switches or cable causing it to hang up.
 
"Well what do you know, I unpl

"Well what do you know, I unplugged the esa and it the engine ran fine.....I took the boat out and it was great, I did have a hard time putting it back into neutral but did what you said. Now how do I test the switches as it seem logical to start there. Your help is really appreciated Bob, I had two mechanics look at it and it stumped them. Thanks again..Ken"
 
"well guess what...I am not ve

"well guess what...I am not very smart....I didnt unplug the Shift Assist Module, I unplugged the switches....it ran fine so figured they need replacing....however, I cant find replacements in any omc parts site....any ideas.....also now dont I have to go back and plug in the switches and unplug the ESA module? I do have patience and really want to learn....thanks for you help and patience...KEN"
 
"You need to determine if the

"You need to determine if the shift interupt switch is being activated. It's the one with the roller arm. This is an easy visual check. Just look at the lever that the roller arm rides on. In it's normal (non-activated) position the roller should be down in the 'V notch'. If the roller is up on one of the peaks of the lever then it is activated and doing it's job in which case your problem would likely be a binding lower shift cable. The switches are available but like most boat parts they are overpriced. No need buying new ones if it's a cable issue. If you see that the switch is not activated then you can easily test it with a multimeter.
By the way, the second switch is the 'overstroke' switch. When made, it overrides the ESA. This might explain why you are running good at full throttle."
 
"Maybe this picture will help.

"Maybe this picture will help. After you have shifted into gear or out of gear the interrupt switch roller should be riding in the middle of the notch (see yellow circle) If it's not then you more than likely have a shift cable problem. Have a buddy do some shifting while you watch in this area and see whats happening. Even if the interrupt switch should stick then the overstroke switch should be activated by one of the cams which should cause the ESA to turn off.

216925.jpg
"
 
"Thank you all very much for y

"Thank you all very much for your help....it was the bottom switch that wouldn't kick off as the lever was sticking on the bottom lock washer of the screw that holds the interrupter switch to the motor....after testing the switch with the ohm meter I found it was working so had to be something else. I then looked at the linkages to see if everything was sitting right. That is when I noticed that the switch lever would stick so I took the lock washer off and all is working fine now. Wow, what a horrid system that such a small problem can cause such a big operational problem. Again, thanks for your help, I couldnt of done it without you.

Sincerely Ken"
 
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