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broncotw
10-29-2009, 06:21 PM
I own a 1985 MasterCraft Prostar Stars and Stripes with a 351 Windsor....

The last four (4) times I have taken the boat out it runs GREAT and STRONG for approximately two (2) hours and then all of a sudden it begins to bog down as if it's starving for fuel. It becomes very hard to start if it starts at all. The last time I took it out it would start and then every time I put the boat in gear it would stall....

After the first time this happened I changed the in-line fuel filter and it contained approximately two (2) inches of black particles almost resembling coffee grounds. I sunsequently changed the entire fuel filter assembly. I soon thereafter took the boat out again and the SAME problem happened again.

Next, since changing the entire fuel filter assembly, I have also changed the following: entire fuel line, fuel pump, carberator, spark plungs, spark plug wires, PVC value, distributor cap and rotor, and ignition system (replacing the old point system with an electronic PCM kit). In my mind, I thought I have addressed all of the potential items that possible could be causing this problem.

To my surprise, I took the boat out this past weekend, and the same EXACT thing happened again! Boat ran GREAT and STRONG for 2 hours and then began missing and then stalling and it was hard to start. Again, as in before, if the boat started once it was put into geat it stalled.....

I hae NO idea what else to look at here......

My only thought is maybe there is some sludge in the fuel tank that is gathering at the pick up point inside of the fuel tank thus preventing the fuel from being sent to through the system -- and this seems to happen at approximately 2 hours into running the boat which equates to 1/2 of the fuel being expended from the tank..... I have no idea if there is a screen or mesh covering over the fuel pickup inside of the fuel tank....

I am at a total loss here....

I would love to hear some ideas and thoughts from some of the members here as to what this could possible be....

Thanks,

Ted
(210) 393-1228

wheeler
10-30-2009, 10:26 AM
What is the temperature getting up to after 2 hours of hard pulling?

My 93 stars and stripes did the same thing, but is was getting hot and vapor locking on my. I run the blower all the time...there is a carb fix on the boards here for that somwhere...

Jim@BAWS
10-30-2009, 10:32 AM
OK what happened to this thread?????

The Mods have gone CRAZY

Jim@BAWS

TMCNo1
10-30-2009, 11:00 AM
There are two identical threads with different headings in General Discussion and they have not been combined yet, http://www.mastercraft.com/teamtalk/showthread.php?t=33173
He didn't get any answers in one minute, so he started a second thread!:rolleyes:

Hollywood
10-30-2009, 11:57 AM
Does your fuel tank have a check valve at the fuel line? Is the vent open and clear? Did you replace your ignition coil?

broncotw
10-30-2009, 07:26 PM
Yes -- it is a brand new coil!!!! I am assuming the "Check value" you are referring to is the anit siphon value! I will check that this weekend and report back!!! Thank you!!!

broncotw
10-30-2009, 07:27 PM
The temperature after 2 hours of hard running was approximately 170 degrees.... Thanks!

ttu
10-30-2009, 07:30 PM
not trying to highjack your thread, but are you coming up to stillwater for a little fun with the cowboys on halloween night?

go cowboys!!

broncotw
10-30-2009, 07:36 PM
No I was NOT in a hurry to get answers and subsequently reposted.... It was my first day on this site yesterday and I am still a "Newbie"!!! LOL I REALLY appreciate ALL of the responses I have receivced! You'll have been GREAT!!! I will check all of the suggestions this weekend that have been made and report back asap!!!

broncotw
10-30-2009, 07:59 PM
I wish! I have season tickets in Austin but could NOT get the for that game!!!! Good luck! Hook Em'

broncotw
11-11-2009, 11:25 PM
Update:

I removed the fuel tank tonight and the entire bottom of the tank is covered with a black sludge.....

In addition, the fuel pick-up inside of the tank is completely corroded..... I am assuming this is the problem or at least a major contributor.....

Does anyone have a good idea on how to remove the sledge from the bottom of the fuel tank? I am considering taking it to a car wash and using a high pressure sprayer to clean it out and then an air compressor to dry out the tank before re-installing it.....

Any other suggestions would be appreciated...

Thanks,

Ted
210-393-1228

FrankSchwab
11-12-2009, 12:42 AM
The Pressure washer sounds good to me - although I'd make sure it was dry before I started (no reason to dump gas down the drain), and I'd put a sheet on the ground to collect the crap (it's better to dispose in the dump rather than the treatment plant). Depending on how firmly the crap is attached to the tank, some time with the garden hose may be all that you need.

Leave it open, propped up so that all the water drips out, and in a couple of days it should be perfectly dry inside. If you want to force air through it, the shop vac may be a better choice than the air compressor. Outside, of course.

One additional thing that you may want to check is the fuel vent - verify that it's clear. If it were plugged, you might see a similar problem.

TayMC197
11-12-2009, 01:44 AM
Cleaning the tank is always good but I think it might not be your problem.
If the engine was going to vapor lock, then I would assume it would happen faster than 2 hours and the engine temp would be high. The fact that it kills when put into gear would make me assume the transmission is seizing.
Is it possible on these transmission to do that? I have seen it on dirtbikes before, where the trans cases were dry/low and bearings where seizing after being heated for awhile(few hours). Then they would cool and run again, it later blew the tranny's though. These were on race bikes though, riders felt if they had less fluid then it would be less weight. They felt it would make them faster. It was a gamble wether there bikes lasted a full day of racing.

broncotw
11-12-2009, 09:57 PM
Thanks for ALL of the suggestions, thoughts, and assistance.... At this point my only alternative is to clean all of the sludge out of the tank and to replace the fuel intake pick-up inside of the tank..... The entire bottom of the fuel tank contains approxiamatley 1/16" of black sludge...... I will flush out the tank and report back with the results.... Hopefully this will solve hte problem......

CruisinGA
11-12-2009, 11:52 PM
Have you tried loosing the gas cap when the boat begins to stall? I've had problems on older vehicles where a failed gas cap would cease to vent properly and a vacuum would build up in the tank, increasing strain on the pump and slowing the flow of fuel to the engine. My understanding is that our boats have a seperate vent, perhaps that is clogged?

thatsmrmastercraft
11-13-2009, 12:24 AM
C'mon guys. You are trying to reinvent the problem. He is stalling out under power after running for a couple hours. His tank is full of crud, and his intake is corroded. When his fuel level gets down, he is picking up loose crud and starving for fuel.

Ted, you might have to actually scrape loose the crud in the bottom of the tank. I'm thinking scraper, 3 foot piece of molding, duct tape and elbow grease. Good luck. Be sure to keep us updated.

FrankSchwab
11-13-2009, 01:42 AM
OK, if thatsmrmastercraft is right, there's a very easy way to find out. Take the boat out without filling it up, and put a full 5 gallon gas can on the swim deck (a bit safer place to carry it, doncha know).

Run it till it chokes. Add 5 gallons of gas. If the problem goes away, it's a pretty absolute indicator of a problem with fuel level.

I'm not buying that the fuel level gets low, the crap blocks the intake, he refills the tank and the crap magically disappers. I would buy that perhaps he has a pinhole leak in the fuel pickup tube; once the fuel level gets low, the fuel pump starts sucking air rather than fuel. I would buy that there's enough black crap in the fuel filter or fuel lines, or that the fuel pump is getting weak enough, that when the fuel level gets low, the fuel pump simply can't suck the fuel high enough to get it to the carb.

Good luck, man. Keep us posted.

/frank

AZDave
11-14-2009, 04:45 PM
It sounds like some componet in the fuel system is degrading to leave that residue. Pull the tank, and go through everything from the tank to the fuel pump