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View Full Version : Need Help/Confused and Puzzled!!!


broncotw
10-29-2009, 07:20 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

jipster43
10-29-2009, 09:39 PM
Which carb are you running?

JP :)

broncotw
10-29-2009, 10:31 PM
Holly 650! Its brand new as I replaced the old one!

Panda Cub
10-29-2009, 10:36 PM
I would definitely take a look at the fuel tank, fuel pump, fuel lines, etc. make sure nothing is clogged....

Maybe water in the tank?

ski_king
10-29-2009, 10:43 PM
Maybe the anto siphon valve inside the tank?

Try giving skidim a call and see what they say.

broncotw
10-29-2009, 11:05 PM
Thanks!!! Do you have the number for Skidim?

ski_king
10-29-2009, 11:07 PM
just go to skidim.com and look around.... u will find it

broncotw
10-29-2009, 11:13 PM
Thank You!!!

ski_king
10-29-2009, 11:13 PM
By the way, by looking at your profile picture, I don't think you boat is an 86. Looks more like an 83 thru 85.
86 didn't have stars and stripes, it had a rainbow stripe package that year.

Does it have a PCM or Indmar engine conversion?

Jim@BAWS
10-29-2009, 11:18 PM
a) Anti Syphon valve on top of tank

b) Sounds like VAPOR LOCK from heated fuel.

c) Edited post...did you bypass the ballast resistor when you installed the BREAKERLESS ignition?

After you run the boat hard let the motor idle down then cool for a few minutes MOTOR RUNNING. Motor box open.
Let the motor box remain open till your next start up. Then close it after a minute or so then ski. Then repeat the procedure. See if that affects your performance in a positive way

Jim@BAWS

broncotw
10-29-2009, 11:21 PM
My bad -- its an 1985..... PCM conversion....

broncotw
10-29-2009, 11:25 PM
Tell me more about the anti syphon value! Can that be replaced? As for Vapor Lock -- why did this suddely start now as opposed to the other 20 plus years? Do the 351W typically have problems with vapor Lock? Thank You VERY much for your input!

Jim@BAWS
10-29-2009, 11:32 PM
Tell me more about the anti syphon value! Can that be replaced? As for Vapor Lock -- why did this suddely start now as opposed to the other 20 plus years? Do the 351W typically have problems with vapor Lock? Thank You VERY much for your input!

Go with VAPOR LOCK suggestion first

ski_king
10-29-2009, 11:39 PM
Agreed on going with vapor lock first. But maybe a bit strange this late in the season, I would expect it to happen when it is HOT out.

Did something change on the boat recently?
Is the motor box vented on the back?

Also did you check the tank fr more contamation? If the flter had coffee ground like material in it, it may have plugged again.

I hope you hung on to all those old parts, some/most may still be good.

broncotw
10-29-2009, 11:46 PM
No nothing has changed on the boat recently! The air temperature was approxiamately 75 degrees and the water temperature was close to the same... Assuming it was vapor lock -- my only question there is would not the engine be at max temperature after running hard for 15 minutes? It would not take a full 2 hours for the engine to reach max temperature... The motor box is vented -- I think -- does it not come vented from the factory?

TMCNo1
10-29-2009, 11:48 PM
Thanks!!! Do you have the number for Skidim?

Here ya go, http://www.skidim.com/contactus.asp