Spark plug question for Indmar Assault in 2014 Moomba Mondo

[Tommy2slow]

Is your fuel fresh? Those misfires could be a symptom of stale fuel. Try adding a bunch of fresh fuel to the tank and go for a blast before turning to expensive repairs.

[bjrow]

Thanks for your suggestion, have trialled that without success.
Smells like unburnt fuel coming out the exhausts when running badly, figured I'd try the ignition stuff then if no good must be fuel related, it's off to the doctors if that's the case.
Cheers BruceR, Melb AUS.

[Holdmybeer]

Thanks for your suggestion, have trialled that without success.
Smells like unburnt fuel coming out the exhausts when running badly, figured I'd try the ignition stuff then if no good must be fuel related, it's off to the doctors if that's the case.
Cheers BruceR, Melb AUS.

Bruce,

If you are smelling unburnt fuel, you are on the right track.
Ignition components most likely. I would guess coil if you did the plugs already. Try running platinum plugs this time. They are a little hotter and are gapped at 0.60 for catalyst motors.
Only other thing it could be after that is leaky fuel injectors from gummed up old gas or carbon deposits.

Cheers

[bjrow]

Right, just in from doing the plugs and coil module.
We've owned the boat from new, the plugs in it originally were marked as 41-101 and were gapped at 0.060", all 8 of them. The Moomba owners manual says 0.040" as well as the Indmar engine manual for 2012 thru 2014. I ended up gapping the 41-993's at 0.060" and put them all in. Started the boat and it ran somewhat same as before for the 20 or so seconds I let it. Replaced the coil and module assembly and ran it again, quite a noteable change in the way it ran. Initially was hunting (cold start) and as it warmed over 15 secs or so the hunting smoothed out to a steady cold start rpm speed, phew!. Let everything cool down over a few hours (cat exhausts were only warm to the touch after running) then ran again, nice smooth cold start idle straight up. Seemed very eager to run compared with what I had become used to. Will test on the hose for hot idle then take to the lake in the next week or so. I did notice on the original coil a dot of paint that was red in colour, the new one (bought from Indmar parts here in AUS) had a blue dot of paint, not sure what that is supposed to reference if anything at all. Maybe someone knows and can chip in.....
So far pretty happy, just have to wait for the rain to clear and give myself a day off during the week.

Appreciate all your comments and suggestions.

Regards BruceR, Melb AUS.

[bjrow]

Great to see this site up and going again, a great resource for all.

Continuing on from the last post, had the boat out on the lake a couple of weeks ago and it all ran great!
Spent about 2.5 hrs running around varying the speed and a bit of a stint at 4K rpm under moderate load and no probs at all, happy days.
Essentially I think the coil and module was the main issue, spark plugs, rotor and distributor cap were worth the effort to changed tho based on how they looked when inspected. Bought another coil and module assembly to have on the shelf "just incase" for the years ahead.
Spark plug gap left as 0.060 as per that found on the originals.
Hope the info helps someone out in the future.
Now for some warm non-windy days.....

Regards BruceR, Melb AUS.

[bjrow]

Got out again on the weekend and had a bit of fun, more of a shakedown before it gets all Winterized.
Goes well!!
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Autumn well underway here.

Cheers BruceR, Melb AUS.