55hp chrysler starts then dies, not sure what to check

[aaron67renken]

I've gotten a lot of help on this ol motor here but now I'm stumped.
It's a 1967 Chrysler 55hp, 5541 I think off memory. It ran pretty good all summer, fire up on the first flip of the switch barely had to use the choke.
The last time in the water I was running at WOT and the engine lost power, and decelerated until stopped. After cleaning the plugs it started and ran for a minute then died again.
I got it home, plugs looked ok, new impeller still worked. I rebuilt the fuel pump (original diaphram still looked good) and rebuilt the carb. I adjusted the carb per the seloc manual. Now it still doesn't want to start and will only run for a few minutes before it dies. And it's "coughing" while running.
Not sure if it's a timing thing, which I planned on looking at next, but no backfires. Or a carb thing (I couldn't get the nozzle out, because of the fixed jet), or something else. It's getting fuel, I can feel it in the carb.
Any ideas guys??
Aaron

 

[eurolarva]

Re: 55hp chrysler starts then dies, not sure what to check

Have you ever had the flywheel off? If so are you sure you torqued it correctly? Sounds like the flywheel key might be partially torn and it is throwing the timing off. When you test it at home is it in a test tank or with water muffs?

 

[aaron67renken]

Re: 55hp chrysler starts then dies, not sure what to check

I have had the flywheel off, I had to replace a coil originally. The key is a new one, I did just what you said previously and ripped a key, and I have torqued the flywheel down with an impact this time. I test it in a tank full above the cativation plate.
My next step was to do the timing and gap check per the manual, but I wasn't sure if I was missing something else.

 

[eurolarva]

Re: 55hp chrysler starts then dies, not sure what to check

If key is fine I would check the points. The reason I asked about the tank or muffs if if you only are firing on one cylinder you might not notice it with the muffs where you would with the tank. Would not hurt for you to re test spark on both cylinders.

 

[aaron67renken]

Re: 55hp chrysler starts then dies, not sure what to check

Well the key is ok, the points look good as well, fairly clean and only a bit off from the correct gap width. So I'm still a bit confused. The seloc manual says that to check the timing there are timing marks on the flywheel but mine doesn't have any and the rod isn't same, they show a hex rod, mine is round.
I didn't get a chance to start it yet again as it started raining. I appreciate your help so far, anything else to check?

 

[eurolarva]

Re: 55hp chrysler starts then dies, not sure what to check

I have never worked on the ignition system on mine before so I am of little help. If you dont get the answer you are looking for here try the marine doctor. He might give you something else to check.