Motor starts then stalls

[seattlesailor]

I have written about my motor before and here we are again at the beginning of a new season. I have been out on my sailboat three times this spring and had to return under sail to my slip every time.

It takes a few tries for the motor to start and then it dies after 5 minutes and I have to wait may be an hour to start it again.

When the motor runs it does not sound right as if there is not enough fuel or there is gunk in the carburetor.

I am thinking that I need to replace the main fuel filter and the Moyer filter that I installed 2 years ago when I replaced the fuel pump. Do I need to check the carburetor?

I welcome your input.

Mich

[CajunSpike]

Are you running electronic ignition or points/condensor?

[JOHN COOKSON]

A Couple Of Ideas

Try loosing the fuel fill cap - the tank vent line may be plugged.

Next time, after the engine shuts down, pull the big wire out of the center of the distributor cap and hold it ~1/2" near the engine while turning the engine with the starter. A blue-white spark is good. This will let us know if the coil has a problem.

TRUE GRIT

[Bratina]

When the motor runs it does not sound right as if there is not enough fuel or there is gunk in the carburetor.

I am thinking that I need to replace the main fuel filter and the Moyer filter that I installed 2 years ago when I replaced the fuel pump. Do I need to check the carburetor?

I welcome your input.

Mich

I had an issue where the engine wouldn't idle, and became progressively worse. On removing the small polishing filter I found that it was almost completely blocked, and replacing it solved my symptoms.

I would remove the polishing filter and try to blow through it (don't get gas in your mouth...). A new filter has very little resistance. A fuel pressure gauge would, of course, have highlighted my issue almost immediately.

[edwardc]

...it dies after 5 minutes and I have to wait may be an hour to start it again. ...

Mich,

You may have other problems going, but to me the hour wait is a big red flag to check the coil. This is typical behavior for a bad coil. So let's go at this one thing at a time.

Next time it happens, pull a plug wire and check for spark while its in the "no start" period. A missing or weak yellow spark means a bad coil. Replace it with a Moyer coil which will have the proper internal resistance and not prone to burning out.

As for hard starting, a properly tuned A4 should be a little hard to start and always require full choke for starting when cold. A "too easy" start usually means the mixture is too rich, which will foul the plugs.

By all means, replace the filters. I do this as an annual maintenance item at every spring startup. A fuel pressure gauge right at the carb, after all the filters, will allow you to diagnose this at a glance.

If the rough idling persists after exonerating or replacing the coil, it could be a dirty carb, but check the plugs first to be sure they're clean and gapped properly.

[seattlesailor]

Try loosing the fuel fill cap - the tank vent line may be plugged.

Next time, after the engine shuts down, pull the big wire out of the center of the distributor cap and hold it ~1/2" near the engine while turning the engine with the starter. A blue-white spark is good. This will let us know if the coil has a problem.

TRUE GRIT

I changed my plugged fuel vent cap and vent hose three years ago so I will try this but I do not this this is the problem. Thanks

[seattlesailor]

Mich,

You may have other problems going, but to me the hour wait is a big red flag to check the coil. This is typical behavior for a bad coil. So let's go at this one thing at a time.

Next time it happens, pull a plug wire and check for spark while its in the "no start" period. A missing or weak yellow spark means a bad coil. Replace it with a Moyer coil which will have the proper internal resistance and not prone to burning out.

As for hard starting, a properly tuned A4 should be a little hard to start and always require full choke for starting when cold. A "too easy" start usually means the mixture is too rich, which will foul the plugs.

By all means, replace the filters. I do this as an annual maintenance item at every spring startup. A fuel pressure gauge right at the carb, after all the filters, will allow you to diagnose this at a glance.

If the rough idling persists after exonerating or replacing the coil, it could be a dirty carb, but check the plugs first to be sure they're clean and gapped properly.

I changed the coil last week (not with a moyer) so I will check the filter and plugs. Thank you
Mich

[seattlesailor]

Are you running electronic ignition or points/condensor?

points condensor. Thank you

[Dave Neptune]

Note, it takes the a-4 approximately 5 minutes to run the carb out of fuel.

When it dies and you have spark it is fuel delivery either to the carb or an internal blockage in the carb.

Gas running out the engine will stumble and sputter to a stop. If it's spark it will usually just quit like you turned off the key.

Dave Neptune

[Jimmy]

Did you know......

Seattlesailor
For what it’s worth.....Your symptoms sound very familiar to my issue several years ago. I chased the same sudden stall/failure to start issue for months.
As I was going thru the list of possibilities, I changed my coil early in the process, but was ignorant to the fact that leaving the key in the “run’’position could damage the coil. As I was frantically checking/changing/diagnosing the cause, I cooked the new coil.

On the up side, when the problem was resolved, I had a newly rebuilt fuel and ignition system I also added a buzzer to indicate low oil pressure-aka leaving the key in the run position with engine off

Cheers
Jimmy