H280 soot in cabin

May 15, 2015
131
Marlow-Hunter 31 Everett, WA
My H280 has had a long-standing problem with strong diesel fumes in the cockpit and--on longer motoring trips, 4 or 5 hrs--we find traces of soot in the cabin (e.g., on white plastic glasses or plastic bags in the cabinets). What’s puzzling is that there’s no sign of an exhaust leak that I can find (using the soap bubble test), the engine runs well, doesn’t seem to be burning oil, and there’s absolutely no evidence of soot in the engine compartment itself or the muffler & exhaust hose aft of the engine. Based on previous feedback on this forum, I installed a new mixing elbow (since it had never been replaced), but this has not helped.

So now I’m thinking that the soot inside the cabin must be coming from exhaust output from the stern, drawn through the companionway door or some other opening in the boat. Does this seem likely? Has anyone else had this problem with a smaller Hunter?

Thanks,

Matt
 
Oct 29, 2005
2,355
Hunter Marine 326 303 Singapore
Possible partial blocked U-Mixing elbow? Exhaust could come out from air intake.
Swipe your finger in air intake nozzle , see if you get carbon.
I do get exhaust coming back to cockpit due to vortex(?) But never into cabin from companionway.

Ken Y
 
May 15, 2015
131
Marlow-Hunter 31 Everett, WA
Thanks Ken...I did replace the u-mixing elbow ~ 6 months ago. Wasn't really blocked, but pretty dirty. But like I said, this did not resolve the problem.

Yesterday I did find and repair a small tear in the exhaust fan hose leading to the cockpit, where it passess beneath the cabin's aft bulkhead...perhaps this will solve the problem.

Matt
 
Jan 7, 2011
4,723
Oday 322 East Chicago, IN
The H280 was a pretty tight engine cover as I recall (sold mine 5 years ago). But I guess some air can get out through the “tunnel” aft of the engine.

Could it be belt dust? My O’Day 322 had a ton of belt dust in the engine compartment when I bought it. Some made its way out around the compartment access panels.

Greg
 
May 15, 2015
131
Marlow-Hunter 31 Everett, WA
I believe I fixed the problem by repairing the engine fan hose, which I guess was blowing engine fumes into the space behind the aft bulkhead and under the cockpit?? I discovered this when holding my hand under the fan vent on the stern with fan turned on--and felt no air coming out. The fan hose has probably been torn/cracked since the last time I removed the aft bulkhead 2 yrs ago.

Ran the boat for a 2-3 hrs today, minimal cockpit odor and no detectable soot in the usual places.
 
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Likes: jviss
Oct 22, 2014
20,989
CAL 35 Cruiser #21 moored EVERETT WA
Good job... Exhaust would be a great source for soot. You just need to keep looking. Love the fact that you shared the outcome.
 

Panera

.
Jan 18, 2014
57
Hunter 280 Portland, ME
Hi Matts, I also have a Hunter 280 1997 version. I'm curious about the engine fan, my boat does not have one?