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I had a problem with engine stalling the last two times I went out.
Idle speed on Intracaoastal to grab fuel, pushed it up on the way home and ... stalled , couldn't keep it running.
Seemed like a fuel issue, so I replaced fuel filters (20 micron).
Two days later,went out it ran fine, hung out by the inlet, started to go home, same stalling issue.
Mechanic friend that does mostly big diesel guys stopped by, he pulled the filter in the carburetor and there was a very fine white-ish powder in the screens.
My tank is aluminum and my fuel (quote,unquote) is ethanol free.
Is my tank starting to corrode ? will stepping up to 10 micron filters eliminate the problem ?
One carburetor had been replaced and was the engine that did not have the stall problem, although it too had some of the powder.

any suggestions .... other than call my local Cummins dealer ?

Boat is in Florida, so it is subject to the high humidity and doesn't get run as much as I would like .... I do add fuel stabilizers.

Steve,you said it call the Cummings guy,our will never regret it

Neil ...
I was hoping for a suggestion that would be perhaps a bit more cost effective :-)

Sure that one of those bags to smuggled did break?

Sorry how old is the tank? You have copper lines to the motors?

You could always head out to Hawaii and look at a set of 315 Yanmars! :)

Steve-
I have a newer (2008) gas tank and ethanol fuel. My boat has 1992 Crusader 454s. My fuel filters have been clean - just dumped them out not cut open. The small screens built in to the base of the carbs have collected some light sort of sandy material but that has not been a problem.
I have been eyeing my fuel pumps (mechanical) and not knowing how old they are, thinking about updating them. if your set-up is like mine the fuel pump is after the main filter but before the carb base filter.
I have also become aware that a great percentage of the 454s with Quadrajet carbs suffer from leaks caused by warping. Over tightening and the heat expansion of the engine may be to blame. A leak at the base of the carb might present symptoms like you describe?
Looking out the window at the flurries I think I should come down and try and help you out in person...
Happy New Year,
Stephan

Scott ... what you are referring to would probably more than pay for the Yanmars that Dug speaks of.

After cleaning those carburetor screens ... engines wound out as they should.

My thoughts are .... I'm gonna switch to 10 micron filters, check fuel tank condition (it was new when installed in boat approx 7 to 8 yrs ago, get some big rudders, because I could not run on one engine with the stock rudders.

Stephan .... the sandy stuff in the carburetor screens is what I refer to .... maybe it was just the buildup that finally got to me. As of this morning, I'm back in NY, so outside of your window looks a lot like mine

Sounds like the same problem that I have with my Yamaha after it has been sitting a while...sticking floats/jets. Engine will start and idle, but will bog/stall when you give it gas. I haven't noticed any sandy residue. My problem seems to solve itself after some running.

If you are running with a low tank you could be picking up crud off the bottom of the tank, or maybe the pickup tubes are corroding, or maybe the inner surface of the tank is oxidizing if it sits for a long time with low fuel levels. I would pull the pickup tubes and inspect them and the inner surface of the tank.

good luck!
Cam

Steve

Good to have you back in the 19 degree weather. Why should you be the lucky one to stay warm.

I agree with Cam. You are picking up some type of sediment. Could be the tank breaking down, could be just bad loads of fuel. How old are the 454's. We had 75 Mercruisers with the Quadrajets. they never had a filter on the carb. Only filter was the spin on and it was after the fuel pump. Never had a problem and ran it that way until we repowered.

Try taking the spin on filter and emptying it out in a clear container and see if you get any sediment. You can cut it open also. If it is clean then you know it is after the spin on. I bet you have sediment in the spin on also. Just a bigger filter, so does not clog as quickly. Now, for all you know, that sediment that clogged the Carb filter, could have taken 5 years to clog up. When was the last time it was changed?

I would carry extra filters and run it to see what happens. Just make sure to change it at least once a year, or 100 hours.

I had issues this year with stalling on one motor---although I did not have any fuel issues----finally tracked it down to a ignition module----after replacing electric fuel pump and coil.

Think I'm gonna replace both carburetor filters and switch to 10 micron canisters .....
The fact that they both had sediment, but the carburetor that was replaced had less, indicates that it may have been a slow build-up.

thanks guys

Steve: The cheapest approach without throwing parts at it is to swap the carbs between engines and see if the problem follows the carb. If not it is ignition.

Craig Mac wrote:I had issues this year with stalling on one motor---although I did not have any fuel issues----finally tracked it down to a ignition module----after replacing electric fuel pump and coil.

I chased a similar problem a few years back and it was the fuel pump.

Steve,
I had 454 Throttle body fuel injection engines in my old 31, no secondary filters , but if the boat sat for a long time without being used I would get the white powder you mentioned. It would show up in the base of the throttle body, I had a fiberglass tank. I think it was caused by the fuel that was left over in the lines drying out in the hot Florida environment inside the engine boxes. I would blow out the lines with compressed air and a spray of Corrosion X , a squirt of fresh gasoline out of a squeeze bottle, after that they would run okay. That was my experience with the white powder substance.
Pete Fallon

It's funny, but Florida always being hot and steamy for boating is both a blessing and a curse......the boats BAKE !!
I'm going to inspect and clean that filter every 6 months.