Author Topic: Marine Quadrajet, e-10 fuel, stored 5m a year, how often should I clean/rebuild?  (Read 4375 times)

Offline LouC

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 Got a related question to the one about the fuel filter. My Q-Jet is an original marine unit on my 1988 OMC/Chevrolet 4.3 V6. I have averaged about 6 seasons between it needing a cleaning/rebuild, this boat is run on E10 gas and stored for approx 5 months each season. Just rebuilt it with Cliff's Marine kit this week.
Usually what leads me to doing a cleaning/rebuild is unsteady idle, stalling, or poor high rpm performance. I'm thinking I should maybe do it at 5 seasons to avoid trouble, thoughts?
Also instead of storing it with e10 fuel in the carb, I was thinking of dumping the fuel filter at winterization and then filling a new one with E0 gas like VP racing fuel. These filters are big like and oil filter so they hold a fair amount of fuel. Then run the engine for about 5 min so the E0 gets into the carb while fogging it. The thought here is the carb will be full of E0 gas when sitting over the winter, might reduce the build up of deposits.....thoughts?

Offline quadrajam

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   Sounds like a good idea to me but I would also add a dose of STABIL to your
fuel tank for the last outing before storage.

QJ

Offline lightning boy

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You may also be able to transfer the fuel out of the tank, and then open the line at the fuel filter draining the bowl too.

Offline Mudsport96

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I run Ethanol free premium fuel in my boat. Just to avoid the problems with Ethanol and watery environments. And other than draining the carb bowls and fogging the cylinders, ive never done any extra like fuel stabilizer. You could drain the e10 before your last trip and put it in your vehicle. Then put say half a tank of Ethanol free premium in and run it to flush any Ethanol out of the system. Hell even throw in some stabil to give an extra peace of mind.  Just drain the bowls.at the end of the season and it should be alright.

Offline Cliff Ruggles

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Here is what I recommend.  When you are finished with the boat at the end of the season shut off the fuel to the carburetor.  Run the engine around 1500rpm's until it sucks all the fuel out of the carburetor.  This insures it will not have fuel drying up in it and leaving behind any residue or "varnish".

As for the fuel in the tank I run Marine or "rec gas" for the first and last tanks of the season.  All season long I just use plain old 87 octane pump gas.  Zero issues for decades now with the boats I've owned doing this.

I'll add here that the same thing applies to small power equipment, chainsaws, string trimmers, leaf blowers, small standby generators, etc.  When you are done with them for the season get them running, dump or drain out all the fuel, then shut off the fuel to the carb and run them until they stall out.  If possible pull the choke just as they stall to suck all the fuel out of the carburetor. 

I have ZERO issues with any of my power equipment here and have been doing this for at least 25 years now.  I don't avoid fuel with ethanol in it, I just make sure it doesn't stay in the tank very long and never in the carb for long periods of time.

I'd also mention here that additives like Stabil and Sea Foam, etc, do NOT protect you from fuel going bad, water absorbing water or clogging up you carburetor.  I work on small power equipment and have for over 40 years now and see ALL the aftermath of folks relying on these products to protect them from bad fuel, which they do not........FWIW......

Offline LouC

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I could add a shut off valve, like I have on some of my power equipment, to run the carb out of gas, it would be good if I could time it to do so while fogging it.
I have found that with power equipment, the engines with float bowl carbs seem most prone to problems, those I drain all of them, the ones with cube carbs like the 2 strokes, don't seem to mind not being run out of fuel. I added a shut off valve to my 2 stroke Toro snowblower just to make it easier/less messy. The only one I leave full is my mower with a Briggs 3.5 hp and the pulsa-jet carb, on these the carb sits on top of a metal fuel tank, if you drain these the tank can rust on the inside....

Offline 77cruiser

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I used to use 87 E-10, but for a long time my FI JD lawn tractor wouldn't run worth a crap so I made the switch to non ethanol 91 which is what's available in MN. JD runs a lot better & I don't worry about green stuff in the carbs now.
Jim