Smoke from exhaust

[liquid_acid]

Boat was driving fine today. Came back a few hours later and started it up and smoke was coming from the exhaust and it was sputtering a bit.

I talked to a neighbor and he seems to think that I need to clean my water filter or my pump is overheating or failing. I have a 98 moomba outback. Has anyone had any experience with this or can help me out with any advise to start with

Thanks guys!

Chris

[REDFIVE48]

When mine was puffing a lot of black smoke and not running well, it was the MAP Sensor. Sorry, don't know how to tell you how to test that except by replacing it.

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[maxpower220]

What color smoke? Have you changed your fuel filter anytime lately? a little more info is needed.

[liquid_acid]

What color smoke? Have you changed your fuel filter anytime lately? a little more info is needed.

I've owned the boat for 2 months so I haven't changed the fuel filter yet. The smoke seemed mostly white with the odd black puff.

[liquid_acid]

So I'm sitting on the boat and have tried a few different things. Here is a little more info.

The carb seems to be getting gas just fine. Sounds like all cylinders are running fine. When I start the boat I have to give it quite a bit of throttle to get it to fire. Once it is fired, and I ease back to an idle, the idle speed slows down until it stalls. As it slows, it starts producing more white/grey smoke. If I rev the engine it seems to run fine at a higher rmp and no smoke.

Would this be bad gas, clogged fuel filter, water in the gas?

Thanks.

[DOCDRS]

I've owned the boat for 2 months so I haven't changed the fuel filter yet. The smoke seemed mostly white with the odd black puff.

what have you changed to give us some info

[liquid_acid]

I haven't changed anything. I checked the oil when taking it out or a test run. Oil has been recently changed.

[liquid_acid]

I took the breather off of the carb and looking in while the boat was running. It seemed to me that it was dumping in too much fuel. There was a stream of fuel coming in the 2 rings at idle. A stream like if you were to run your faucet just at the point it turns from a drop to a stream.

When I give it some throttle, it hesitates then goes and stops smoking. Seems the hesitation is due to dumping too much fuel and the fuel air ratio takes a second to catch up. Once the throttle is engaged, it doesn't smoke anymore. Onc you bring it back down to neutral, it I fine for about 10-15 seconds then starts to smoke and bogg down to the point of stalling. The smoke smells like fuel. I think it's running way too rich and I might need to change the spark plugs, and adjust the fuel flow or have my carb rebuilt.

What do you guys think?

[cornrickey]

stuck floats. carb rebuild time

[cornrickey]

try tapping on the carb lightly when it's running to see if you can break them loss to get you through the weekend but more than lightly there not stuck, there being kept open by crud stuck between needle valve and float.

[86century]

Has this thing back fired or made the little half turn backwards when you shut it off.
If so the power valve in the carb could be blown.

[maxpower220]

That is probably pretty on target. I would try to change out the gas, replace the fuel filter, and rebuild the carb. If you are not going to do the work yourself, compare the cost of a rebuild (@ $300) to the cost of a new carb (@ $650). If you are quoted a rebuild much higher than that, shop around.

[liquid_acid]

Has this thing back fired or made the little half turn backwards when you shut it off.
If so the power valve in the carb could be blown.

It has sputtered a couple cranks as I shut it off.

Ya thinking I'm going to go ahead and rebuild the carb and change the plugs and fuel filter. As for the gas, my truck is running low.

[zabooda]

As an owner of a 98 Mobius and being a non-mechanic type, I concur that the carb is the culprit. It is easy to run the gas out just by disconnecting the line at the carb, pull the line out and put it into a gas can. Run a jumper from the battery or accessory plug to the positive on the fuel pump and pump away. Have the boat slightly downhill to get all the gas. In the future, I run a couple of gallons of ethanol free gas with Stabil through the system when winterizing and fog the carburator. In the spring, I pump all of the remaining gas and crud out of the tank into a gas can and replace it with fresh gas. Then I use carb cleaner to get rid of the fogging oil. I haven't had a carb problem yet but you have to keep up on it.

[liquid_acid]

Thanks guys! This forum is awesome.

Let you know how it goes.

[cornrickey]

I screwed around with rebuilding mine. summer is to short to take it in over and over. A holley 4160 from Jegs is under 6hundy.

[liquid_acid]

Ordered the kit from inboardonline.com and just waiting to get this going.