Hi again,
Still working on this old motor with a lot of success but require a bit more information.
The background:
3.3 Mile master fuel tank with excellent pressure and good hissing sound when cap is loosened at end of run. No leaks.
Motor starts well and runs well at WOT and at idle. I get many compliments at the dock from people who see this motor and hear it running.
However, if at idle for an extended period of time, say 45 min. to an hour some missing[misfiring- spluttering, like you would think a bit of dirt was going through] is evident when trolling. Engine does not quit, but starts to run unevenly. It will level out again and then start to miss a bit again[still trolling] A bit inconsistent. Can take it back up to WOT with no problem and can cruise along without missing a beat for as long as I want.
Fuel filter and glass bowl are clean and priming through carb with bowl off is very good. Bowl stays full of fuel when running and maintains level in bowl over night; no leaking back through male fuel fitting.
O rings in female fitting have been replaced and there is no leaking at all.
Currently I am using Champion J4C spark plugs at .030 gap.
Needle valves are set according to specs and have been fine tuned on the water for best performance.[And as I said, most of the time she runs great unless trolling for an extended period of time]
Plugs look very good upon inspection - good colour
Gas tank is clean and new fuel is added to outboard tank through a screened funnel.
Current gas oil/ ratio is 24 to 1 and I realize there are many differing opinions on this.
I have been adding Sea Foam to my mix at 2 oz. per gallon and am on about my third tank.
I have good water circulation coming out of the motor.
So what do you think might be causing this spluttering[misfire] after say an hour of running?
I would expect that if it were ignition coils the problem would be apparent after a warm up of the engine.
Would I be better to use J6C plugs, which I have? What about B6S NGK?
Would changing the lower unit gearcase lube be a good idea?
I have a hunch that the problem has a simple solution as most of the time I have good performance. I am not fearful of the motor leaving me stranded with only the oars to rely on. I can turn it off to cast for a while if I want and it starts right up on a pull or two.
I look forward to any and all input on this topic as your experience is very much appreciated.
Thanks,
Sean.
Still working on this old motor with a lot of success but require a bit more information.
The background:
3.3 Mile master fuel tank with excellent pressure and good hissing sound when cap is loosened at end of run. No leaks.
Motor starts well and runs well at WOT and at idle. I get many compliments at the dock from people who see this motor and hear it running.
However, if at idle for an extended period of time, say 45 min. to an hour some missing[misfiring- spluttering, like you would think a bit of dirt was going through] is evident when trolling. Engine does not quit, but starts to run unevenly. It will level out again and then start to miss a bit again[still trolling] A bit inconsistent. Can take it back up to WOT with no problem and can cruise along without missing a beat for as long as I want.
Fuel filter and glass bowl are clean and priming through carb with bowl off is very good. Bowl stays full of fuel when running and maintains level in bowl over night; no leaking back through male fuel fitting.
O rings in female fitting have been replaced and there is no leaking at all.
Currently I am using Champion J4C spark plugs at .030 gap.
Needle valves are set according to specs and have been fine tuned on the water for best performance.[And as I said, most of the time she runs great unless trolling for an extended period of time]
Plugs look very good upon inspection - good colour
Gas tank is clean and new fuel is added to outboard tank through a screened funnel.
Current gas oil/ ratio is 24 to 1 and I realize there are many differing opinions on this.
I have been adding Sea Foam to my mix at 2 oz. per gallon and am on about my third tank.
I have good water circulation coming out of the motor.
So what do you think might be causing this spluttering[misfire] after say an hour of running?
I would expect that if it were ignition coils the problem would be apparent after a warm up of the engine.
Would I be better to use J6C plugs, which I have? What about B6S NGK?
Would changing the lower unit gearcase lube be a good idea?
I have a hunch that the problem has a simple solution as most of the time I have good performance. I am not fearful of the motor leaving me stranded with only the oars to rely on. I can turn it off to cast for a while if I want and it starts right up on a pull or two.
I look forward to any and all input on this topic as your experience is very much appreciated.
Thanks,
Sean.
