runs bad

[DonziChris]

Hi guys, thought you might be able to help. I just bought a 1993 18 classic, was told by the person I bought it from that it had not been used last year. I drained out the fuel tank and put in fresh gas, replaced the fuel filter, and oil and filter, cleaned the carb. put in new plugs, took the boat out it ran fine for about five minutes, than quit let it sit for a minute restarted. Boat would idle but would quit if you gave it any throttle. This boat has a omc 351 ford in it. This boat may have sat more than a year. Does anyone think they know what might be wrong or what I should try next. Thanks Chris

[maddad]

My boat sat for 4 years with about half a tank of gas. I drained and filled with fresh and got what happened to you. A ring of jelly like yuck skirted the tank at the old fuel level and would slowly wash off with the sloshing new fuel. Clogged filters regularly for a while, then every so often, finally I changed the tank. I opened the old tank, that I was using for 2 seasons, and there was still a lot in there.

[MOP]

Short of pulling the boat apart what you can try one of two things, aprofessional tank cleaning service or what has worked on several boats I have worked on over the years. Put a couple of gallons of acetone in the tank then top it off with gas, rebuild the carb it is more then likely full of varnish. Remove and check the anti siphon valve they can get gummed up. Buy a box of filters and check them every 20-30 minutes of run time, the first few will crap up pretty quick after a few hours you should start to see the fuel getting cleaner looking. Keep the runs short and take it easy on it with no full throttle stuff until the filters show clean gas with no discoloration. Once it cleans up you should be good to go!

[Cuda]

Definetely a fuel problem, most likely in the carb, I think.

[DonziChris]

Thanks for the suggestions guys. I talked to a mechanic friend of mine and told him I had put some plastic fuel line on the end of the steel fuel line where it goes into the carb in order to see what kind of flow I was getting out of the fuel pump, and also to see if there was any junk in the fuel which there was not. At that time I noticed that the fuel flowed back down into the fuel pump when I stopped cranking the engine, He said it should not flow back into the fuel pump, that I had stuck check valves And should change the fuel pump, or possible clean the debri out of this one. I think I will change the fuel pump first, and see what happens. If that does not fix it then I will have to check into the tank. Hope its not the tank as that can be a big job. thanks for the help, I will let you know how it turns out. Thanks Chris

[DonziChris]

Tried to get a fuel pump today no luck, Had to order it won't be here until Friday. So I took the fuel pump apart and cleaned it, looked like all the what looked to be paint had all peeled inside the housing. Cleaned it all out including the check valves. checked the screen at the fuel inlet at the carb it was clean. Took the boat out ran better than it has since I bought it but still not perfect, Will put new fuel pump on this weekend, and go through the carb one more time. Hope this does it. Chris

[Cuda]

Is the carb a Qjet?

[MOP]

Joe 99% it is a Holley that is what most Ford packages came with, the paint flakes in the pump is the dried varnish coming loose. That was the reason I recommended the acetone, it is one of the best things to help to dissolve the varnish. You need to break that stuff down so it does not continue to clog stuff up.

phil

[BigGrizzly]

Take the screen off the fuel pick up, if it has one, then put a big fuel filter befor the fuel pump and go for it. You can use a fuel additive like a injection cleaner or Sta- bil, this helps too.

[DonziChris]

Yes it is a holley carb, Will be changing the fuel pump hopefully this weekend. And a carb rebuild kit. Hope the tank is clean if it sat for a year or two, I pumped out all the old gas. Using acetone in the fuel tank makes me a little uneasy.

[MOP]

Yes it is a holley carb, Will be changing the fuel pump hopefully this weekend. And a carb rebuild kit. Hope the tank is clean if it sat for a year or two, I pumped out all the old gas. Using acetone in the fuel tank makes me a little uneasy.

Not to worry read the post below!
http://www.donzi.net/forums/showthread.php?t=38955&highlight=acetone

[DonziChris]

Hi I just put on a new fuel pump and the rebuilt carb. Will be going out first thing in the morning. Wish me luck sure am excited, can't wait to see how she runs. Will let you guys know tomorrow. Thanks Chris !

[slamdry]

dumo a can of SEAFOAM engine treatment in the tank, it does wonders for helping to clean!!

[DonziChris]

Thanks Brian I will try that. Thanks Chris

[DonziChris]

Took the boat out early this morning, Ran fine for about 20 minutes then would not idle. The boat would run fine off idle, Ran the boat for about an hour. Ran into a mechanic friend who looked at the carb, and while we were turning out the air screws he said rev it up, when I did, it back fired once and instantly started to idle on all 8 cylinders. He thought a piece of crap may have been caught in the power valve making it run rich at idle. Boat ran and idled fine after this. Boy am I happy, this sure is one fine and fun boat. I need to take it easy for a while as I caught air a couple of times. Thanks for all the suggestions. Talk to you guys soon. Thanks Chris

[DonziChris]

The new fuel pump, And rebuilt carb seems to have done the trick. Boat runs fine, this is the most fun I have ever had in a boat. I have been bitten by the donzi bug. Take care Chris

[MOP]

The new fuel pump, And rebuilt carb seems to have done the trick. Boat runs fine, this is the most fun I have ever had in a boat. I have been bitten by the donzi bug. Take care Chris

Thanks for the follow up post it is always nice to hear things turned out GOOD!