Burning rubber smell in cabin when running Genny and AC

[sb in gp]

This one has me stumped. Changed the impeller on genny which was in pretty rough shape. Pulled many fin parts from the genny aftercooler. When I run AC and genny I get a noticeable smell of burning rubber in cabin. Genny is pumping water great. No smell when using AC and plugged in.

 

[BlueYonder]

I had an impeller self destruct after the intake strainer became clogged with sea nettles. Some of the rubber pieces made it into the exhaust elbow where the hot exhaust combined with rubber impeller pieces caused a burning rubber smell.

 

[SeaAyeOwe]

So if I understand it these are the conditions, there is no smell when you run the genny alone. There is no smell if you run the AC from shore power. There is a burning rubber smell when you run AC powered by the genny in the cabin.

If those conditions are true it seems to tells you the burning rubber smell is a problem with the AC pump motor when on genny meaning that a voltage problem is occurring on the genny, or the load that the AC unit is putting on the genny is overloading the genny some how, or the electrical cable and switches that feed genny power to the crossover switch has a problem.

I would double check the voltage of the genny when it is running first. I would make sure the genny switch over panel in the cabin is not the source of the smell. If those two are OK it seems like the load on the genny is too much for some reason and when on shore power it is not an issue because it is over the genny load but under the current capacity of shore power.

 

[oceanpearl]

Just a thought. Had a rubber odor while cruising and also thought it might be an impeller issue.
Turns out it was an exhaust hose leading to the muffler that was breaking down on the inside.
When removed it was bubbled up and smelled burnt rubber. Replaced and solved the issue.
I believe you must have an exhaust hose leading to the genny muffler.
Check it out. My 2 cents.

 

[dvx216]

If your genny checks out mechanically you might went to check all your electrical connections between the breaker panel and the generator. Your Ac unit has a largest amp draw then most things on your boat

 

[CliffA]

If your genny checks out mechanically you might went to check all your electrical connections between the breaker panel and the generator. Your Ac unit has a largest amp draw then most things on your boat

+1...sometimes a loose wiring connection can case a wire to heat up to the point the insulation on the wire starts to melt....this can produce a 'rubber' type smell...

cliff

 

[MasterFab]

I'd start simple - check your belt tension on the genset. A slipping belt gets hot, and that burning rubber smell is the result. You may also notice fine black particulates surrounding the front of the generator.

Dale

 

[Alex F]

This one has me stumped. Changed the impeller on genny which was in pretty rough shape. Pulled many fin parts from the genny aftercooler. When I run AC and genny I get a noticeable smell of burning rubber in cabin. Genny is pumping water great. No smell when using AC and plugged in.

I would start by verifying the exact symptoms that cause the smell to occur.


You statement "...When I run AC and genny I get a noticeable smell of burning rubber in cabin..." implies that genny (or any of it's components) is a possible cause. To verify this theory, I'd say that you should be able to go in the ER and smell something coming from the genny when both (salon A/C and Genny) are running.


In this scenario (if genny is at fault), there's a small conflict of the theory. The salon A/C is a self contained unit, which has return right at the unit and it pulls the air from the salon via small openings under the entertainments center and the STBD side couch. It's very unlikely that it's pulling the smell generated in the ER area.


BTW, I'd say that stove with both burners ON, would be your biggest "juice user". In any event, it's easy to get the AC load going to verify if the salon A/C unit could be a contributor to the puzzle.

 

[fc3]

Isolate the electrical problem first. Run the generator with the main breakers on the genset set OFF and the air conditioning on shore power. If the odor still exists, it's not an electrical problem. If the odor does not exist, then it's probably electrical. The other suggestions are good items to check but why check both electric and generator systems when it's so easy to possibly eliminate one?

 

[sb in gp]

Thanks for all the suggestions. Ran the genny for about 30 mins with shore power and AC on and no smell. Then switched to genny power with AC on and ran for another 30 and still no smell. Hoping I had an impeller fin in exhaust and it finally cleared. I'll see.

 

[Alex F]

My logic tells me it's highly unlikely to have these two events related. But, I'm glad the smell is gone. It could very well be just a coinsidence.

 

[sb in gp]

For what its worth - the smell did not have an electrical smell to it. As a tinkerer I've fried a lot of wires and this did not smell like wires melting. I hope this helps clarify.

 

[Flying Cloud]

AC Belt?

 

[sb in gp]

Possible but it only seemed to occur on genny.

Didn't know there were belts on these cruisair systems.

 

[Dan Johnson]

This one has me stumped. Changed the impeller on genny which was in pretty rough shape. Pulled many fin parts from the genny aftercooler. When I run AC and genny I get a noticeable smell of burning rubber in cabin. Genny is pumping water great. No smell when using AC and plugged in.

I’m a bit late to the game, but am having similar issue in our 510 Sundancer. Onan Gen set, burning smell only while at anchor under gen power, don’t smell while under way or at dock?

 

[Maybe A Dancer]

had a similar problem with my 10 meter diesel.

Turned out to be blow-by from the genny.

not an issue when underway, as the engines consumed enough air to maintain constant circulation in the engine room.

Was noticeable on the hook

HVAC unit was based in the engine room, as was the ducting.

Had to run the blowers to correct the problem

Eventually replaced that gen set with a NORTHERN LIGHTS

POOF - problem gone

BEST !

RWS

 

[techmitch]

had a similar problem with my 10 meter diesel.

Turned out to be blow-by from the genny.

not an issue when underway, as the engines consumed enough air to maintain constant circulation in the engine room.

Was noticeable on the hook

HVAC unit was based in the engine room, as was the ducting.

Had to run the blowers to correct the problem

Eventually replaced that gen set with a NORTHERN LIGHTS

POOF - problem gone

BEST !

RWS

@Dan Johnson