Infrequent sputtering, 4 o'clock Charlie

[a1nowell]

1984 M/C 470, pushing a 24' JC Tritoon. Carb was professionally rebuilt last year, and recently clean/replaced carb filter, inline filter & water seperator filter. Really found no major contamination.

I can take my boat out and run for 20-30 minutes at a time and she runs great. Then after a little longer run she will start sputtering like 4 O'clock Charlie's airplane on the old MASH rerun. It may do this at various throttle speeds for several minutes and then start to purr like a kitten. I have 2 gas tanks and when she starts to sputter I can flip to the other tank and she continues to do it. She seems to do this more in rougher water.

Any suggestions?

Larry

 

[Don S]

Re: Infrequent sputtering, 4 o'clock Charlie

Are the two tanks sharing the same vent fitting? Check, don't assume.

 

[a1nowell]

Re: Infrequent sputtering, 4 o'clock Charlie

No Don, each tank has it's own vent fitting. The only thing shared is the switch valve. Of course all filters are down line from the switch valve.

Larry

 

[Don S]

Re: Infrequent sputtering, 4 o'clock Charlie

Could be an ignition problem too. What's the spark doing when this happens?

 

[a1nowell]

Re: Infrequent sputtering, 4 o'clock Charlie

Don,
I have no clue what the spark is doing, the tach is very eradic when this is going on but I am clueless about the spark.

Please look at this April post and tell me if you think they are related.

http://forums.iboats.com/showthread.php?t=541400&highlight=a1nowell

Thanks,

Larry

 

[a1nowell]

Re: Infrequent sputtering, 4 o'clock Charlie

Don,
I have no clue what the spark is doing, the tach is very eradic when this is going on but I am clueless about the spark.

Please look at this April post and tell me if you think they are related.

http://forums.iboats.com/showthread.php?t=541400&highlight=a1nowelldictionary


Thanks,

Larry

Any additional thoughts???

 

[Don S]

Re: Infrequent sputtering, 4 o'clock Charlie

When was the last tuneup? You could have a coil starting to fail, doubt it, but possible. Even a loose condenser in the distributor could cause the problem. loose connection anywhere in the ignitions system could cause it.