Indmar Assault Carb version Smelling Hot

[cvfuller]

Hi All,

New to owning a Moomba this year and new to this forum. I recently purchased as 2003 Mobius LSV with the Indamar Assault Carb engine and it has 350 hours on it currently. I replaced the impeller shortly after buying the boat and have about 40 hours on the new impeller. I have found when I run the boat above 3800 rpms I start to get a hot/rubber smell from the engine compartment. The checked the temp gage and it reads normal (approx. 180 degrees) and I also tighten the belt to make sure that wasn't slipping. Everything seems fine except for the smell and this does not show up when running it under 3800 rpms. I stuck my head around to see if I could find where the smell was coming from and it seems to be from the back of the engine, possibly around the exhaust manifold.

Does anyone have experience with this or have any ideas with what may be causing this smell?

[SONIC]

Probably a restriction in the exhaust water flow.
A chunk of old impeller, or some lake debris lodged somewhere in the cooling system will get allow the rubber exhaust hose to get too hot and start to smoke/smell.
I'd pull the hoses and flush them out and check for debris.

[cvfuller]

Thanks for the info. What is the best way to to check for this and flush them out? From what I can tell, there are two hoses (one for each side) that go from the block/thermostat into the exhaust manifold. Are those the hoses you are referring too?

[james yarosz]

I have a 2003 Outback ls.(not a V).The intake water hose comes from the bottom of the boat.through the transmission cooler and then to the water pump.There is a screen on the intake side of the trans cooler that can clog with weeds.I have to clean my screen every year and always find weeds in it.This could restrict water flow at high speeds.

[secondsupra2004]

I have a 2003 Outback ls.(not a V).The intake water hose comes from the bottom of the boat.through the transmission cooler and then to the water pump.There is a screen on the intake side of the trans cooler that can clog with weeds.I have to clean my screen every year and always find weeds in it.This could restrict water flow at high speeds.

I'm guessing you don't have a strainer between the the hull pickup and the pump. My 04' doesn't have one and I think I will get one installed. My 89' came factory with one.

[james yarosz]

No,I dont have a strainer.My last inboard ski boat had one(different brand boat) and I never got any weeds in it so when I bought my Moomba I wasn,t too worried about it.Every year when I winterize it I pull the hose off the trans cooler as part of my winterizing,so i back flush the trans cooler with a hose so I dont feel I need a strainer.In my previous boat I had a failure of the impellor and i could smell the rubber exhaust melting right away.I stopped right away,let everything cool and was able to idle back to shore.

[cvfuller]

Thank you for all the feedback. I went through the entire cooling system and did not find any restrictions in the system. The thermostat looked old so I replaced it while I had it apart. I took it for a test drive and the temp is steady at 160 degrees but I am still getting the hot/burning smell when running above 3800 rpms. I stuck my head in the engine compartment and it seems to be coming from the oil filter/valve cover general area. Any other ideas to check?

[parrothd]

Thank you for all the feedback. I went through the entire cooling system and did not find any restrictions in the system. The thermostat looked old so I replaced it while I had it apart. I took it for a test drive and the temp is steady at 160 degrees but I am still getting the hot/burning smell when running above 3800 rpms. I stuck my head in the engine compartment and it seems to be coming from the oil filter/valve cover general area. Any other ideas to check?

Is it the choke on the side of the carburetor? Black round thing.

[cvfuller]

Yes it is. The boat sat for a couple of years unused before I bought it this spring. It seems to be running on the rich side so it could handle a rebuild a tune.

[SONIC]

Are your valve cover vents connected to the flame arrestor on the carburetor?
If not you could be getting blowby into the engine compartment and smelling that.

[secondsupra2004]

Thank you for all the feedback. I went through the entire cooling system and did not find any restrictions in the system. The thermostat looked old so I replaced it while I had it apart. I took it for a test drive and the temp is steady at 160 degrees but I am still getting the hot/burning smell when running above 3800 rpms. I stuck my head in the engine compartment and it seems to be coming from the oil filter/valve cover general area. Any other ideas to check?

Make sure your v-belts are aligned properly and that they are correctly tightened. Also, could you possibly have the packing gland too tight at the driveshaft? Are you getting a slight drip of water when its running or do you have a dripless seal setup? If you have a dripless seal, make sure the cooling water line is flowing to the seal area. The more RPM you run, the hotter it will get. Is there any chance that something fell under you engine in the bilge are and is rubbing on the driveshaft under there?