View Full Version : Boat choking need help

06-15-2009, 04:54 PM
Not a good weekend on the lake.

Saturday blower switch quit working(hoping just a fuse)

then started hearing a whining sound from the engine, sounds like its around the oil filter area, not real sure hard to tell. Boat will crank fine and idle fine, but at higher rpms the oil pressure will bounce a little and the motor sounds like it is choking down. RPMs will bounce also. It almost sounds like the motor is not getting enough fuel to support the demand or filter or something is clogged. I have not had any problems with this before. Boat was summerized at 201 hrs and now has around 240 from this year. Tied back up to dock and let sit, then tested it again. With transmission lockout on revving it sounds fine, but when i go out and attempt to plane off it starts doing it again.

Boat is a 06 Moomba Mobius LSV with Indmar 340 EXCAT. Plan on taking it to the shop when i get back to SC, but currently stuck in Burlington, VT for work so I can't really troubleshoot anything.

Any one ever had this problem or similar? Got to try to explain it to Shop when I get back, but prob going to get them to take it to lake to witness it.


06-15-2009, 11:07 PM
I don't know about the whine so much.

Do you have a carburetor on your engine or is it fuel injected?

Sounds like bad fuel, especially since it is carbureted. If it is fuel injected, then I would suspect a faulty ground to start out with. It could also be a faulty ground with a carbureted engine as well, causing the engine to not produce a clean spark. Easy test for this is to test the pos side of battery to the block of the engine, should get 12 volts.

I would change the fuel filter, and possibly get some water remover for gasoline engines from the parts store and use it per directions.

Post back whether this engine has a carburetor or fuel injection.

06-16-2009, 05:34 PM
boat is fuel injected. and from what i could tell on the lake saturday, battery's are giving 12 volts. they are brand new this year.

06-16-2009, 07:01 PM
Sounds like a misfire.

06-17-2009, 06:37 PM
happens repeatedly, so that would mean one of the new spart plugs from this summer is fouled out.

talked with someone that knows alot about GM engines and he thought it may be fuel pump or fuel filter. If i can every get out of vermont tonight i will be picking the boat up to take to the shop friday morning. hopefully they will not have a 3 week backlog.

Sucks i have a 3.5 day weekend and a broken boat.


06-17-2009, 09:11 PM
Being summerized 39 hours ago I would not think that a fuel filter would be the problem, as it should have been changed.

A plug could be fouled, but I would lean more to a bad plug wire or a hairline crack in the distributor cap, or it is in need of a new distributor cap and rotor.

08-17-2009, 11:16 AM
What ended up being the issue? I've got the same whine and hesitation.

08-17-2009, 06:28 PM
Took it to the shop and after sitting for a week at the shop. Repair guy, took it to the local lake and idled down and back the lake, ran 2000 rpm around lake, 3000 rpm around lake and WOT around lake. No problems. Said it was most likely a little water in the fuel. Madd props to the Barry Capps Marine, bc they could have taken me for a loop and had me replace all kinds of stuff, but they were honest and no problems since. I think the whine was the the fuel pump starving for fuel, early stages of vapor lock. I have had issues with that multiple times this summer. Just leave hatch open when floating or docking. Quick fix is a bottle of cold water poured directly on the fuel pump.

I think the water in the fuel was stemming from the shaft seal leaking toooooooo much. Replaced it and not problems since.

Try putting a bottle of Sea-Foam or Sta-bil in the tank and find 100% gasoline if you can. I run 100% gas 89 octane if i can find it. Few places in town and couple in Columbia where i go mostly.

Good luck.

08-17-2009, 10:28 PM
Hey you can't get water in your fuel because your prop shaft is leaking! Did I read that correct?
You can get water in your fuel from the ethanol they are putting in the gas nowadays! It is especially bad in a motor that is not run very often like a boat.
I have never seen sooooo many vapor lock issues like I have this summer on this board!!! This ethanol has to be considered one of the root causes of this problem!
I also suspect that the v-drives are experiencing this more often than the DD's and that has to be related to fuel line routing and motor box venting.

Here is a blurb from http://www.businessweek.com/technology/content/may2006/tc20060519_225336.htm

Are there any problems with ethanol?
Oh, yes. Ethanol can't travel in pipelines along with gasoline, because it picks up excess water and impurities. As a result, ethanol needs to be transported by trucks, trains, or barges, which is more expensive and complicated than sending it down a pipeline. As refiners switched to ethanol this spring, the change in transport needs has likely contributed to the rise in gas prices. Some experts argue that the U. S. doesn't have adequate infrastructure for wide ethanol use.
Also, ethanol contains less energy than gas. That means drivers have to make more frequent trips to the pump.

It is time for PCM and Indmar to start looking at Diesels as the US Gov. is forcing corn squeezins down our throats, at least Bio Diesel will always burn and is created by using waste from other manufacturing processes (McDonalds french fries) and not creating expensive new ones that just raise the price of the fuel.

08-17-2009, 10:37 PM
Here is a reply on that same website!!!

Nickname: jakesaboy
Review: many boat owners are having engine problems apparently because of ethanol. dealers are selling additives for the hybird gasohol to prevent the engines from seasing-up with vapor-lock. corn is for animal consumption not propulsion
Date reviewed: Aug 4, 2009 1:24 AM

08-19-2009, 09:45 AM
Yes ethanol was definitely the root of the water in the gas. Too much water was referring to the chance that water spashed up to the air filter and got moisture in that way. As far as boat not being run often, that is definitely not the case. I have put over 80 hours on the boat since begging of the summer, including the month of july when it did not get used due to traveling and damn ppl getting married in the summer time.

08-19-2009, 11:44 AM
I've been avoiding the ethanol, but maybe I messed up on a tank. I'm going to start with the fuel filter and a fuel additive to get rid of any water. Thanks for the insight!

08-21-2009, 06:15 PM
A new fuel filter and a couple of bottles of iso heat stopped my fuel pump whine and chugging above 3000 rpm. Thanks for the insight!

08-22-2009, 12:54 PM
The main problem with ethanol and fuel injected boats is that ethanol is more volatile than gasoline, on on boats there is not a lot of air circulation directly around the engine, and the fuel rail collects heat and gets hot, and the ethanol in the gas evaporates, and is not pushed through the injectors, thereby creating vapor in the fuel rail. This can be observed by when it happens you can depress the shrader valve and get a gas instead of a liquid. Ethanol has little to do with extra condensation in gas.

08-22-2009, 12:59 PM
I thought I read where the ethanol picks up water???