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steve
09-17-2009, 05:35 PM
I have a 1988 Mastercraft Pro Star with the Ford 351, Holly 4 B carb
After 40 sec at full throttle the boat act’s likes it is starving for fuel.
I replaced the fuel filter. This helped a little bit but the problem still exists. Boat runs fine except at full throttle.

88 PS190
09-17-2009, 06:07 PM
There may be a screen at the inlet of the carb, possibly a screen on the outlet from the tank.

You replaced the fuel filter on the pump?

steve
09-17-2009, 06:21 PM
I don’t think it was the pump. It was a bowl filter between the water separator and the carburetor attached to the engine. It had a metal fuel line going to the carburetor. I thought the fuel pump was in the gas tank?
Sorry I have very little experiences with this. I bought the boat new and had no mechanical problems with it until now.

88 PS190
09-17-2009, 06:38 PM
If its set up like mine, the fuel pump is mechanical and mounted on the engine as you describe, there's also a bowl on the drivers side stringer down below the engine.

I haven't had to do a lot of troubleshooting in the fuel system, I just drain them when I winterize, so I'm not sure if the one on the engine is the filter or fuel water separator and same goes for the bowl on the stringer. I feel like the one down low is the fuel water separator because it has a drain petcock, again on my boat.

babymoore3
09-17-2009, 07:49 PM
Don't forget air out, air in. Could be a lot of things, don't just assume fuel. Do you have good power initially and it falls off? Is hole shot good still?


Is your secondary opening up? Maybe it is restriction in or out (rust in manifolds), something in the exhaust from winter storage (nest)? One exhaust should be noticeable warmer if this is the case. Another thing to check is your fuel pump - should be the lower left hand side of the engine (looking from transmission to alternator). Unfortunately this is a metal line up to the carb usually. Hard to check fuel pressure...

steve
09-17-2009, 09:23 PM
Boat runs good has good power.
At full throttle good power for 90 sec then it will sputter like it is running out of gas. 30 sec later it really sputters then it will die if I leave the throttle wide open. Wait 10 sec and start fine and will run good.
If I pull the throttle back half way during the sputtering it clears up and runs fine.

It acts like there is not enough fuel flow to the carburetor at full throttle, once the bowl empty’s it starts sputtering. If I back off on the throttle the bowl fills back up and it runs fine.

From what I can tell the fuel lines runs from the gas tank to the water separator then to the bowl filter? Then to the carburetor. I took apart the water separator did not notice any water in it, which I though was strange. I never drained or open it, did not know it was a water separator until now, I am the original owner of the boat. The bowl filter was not very dirty either, replaced it anyway.
Q. Their is a vent on the water separator. What is this for?
Q. How can I check the fuel psi. and what should the psi. be?
Q. Is their something in the carburetor that could be keeping the bowl from filling up at full throttle?

One more peace of info. I had the carpet and upholstery replaced in early spring. They pulled the gas tank. Could the fuel line gotten pinched when they reinstalled gas tank.
Will a psi check confirm this?

steve
09-17-2009, 09:25 PM
How can i post a picture?

88 PS190
09-17-2009, 09:57 PM
I'm surprised it fully dies, from high rpm.

Your oil doesn't have a very gassy smell does it?

For pictures you can use manage attachments from below, or I save them to a photobucket account, and then I use the insert image button (actually photobucket has an option to copy the link with img tags so I typically use that these days)

Footin
09-17-2009, 10:03 PM
How about the fuel pick up in the tank.

TMCNo1
09-17-2009, 10:10 PM
How can i post a picture?

Click on "Post Reply" box or Quick Reply "Go Advanced". In Additional Options below the post box, you will see "Manage Attachments" or click on the paper clip at the top of the post box, there you choose a picture from the Browse feature that is stored in My Pictures, and follow the prompts to upload that picture. If the pic is too large there is a post on resizing in FAQ at the top of General Discussion.

TMCNo1
09-17-2009, 10:13 PM
Also consider checking the springs and weights in the distributor for a broken spring/springs, rust and corrosion that may hinder the distributor from advancing the timing at higher rpm.

thatsmrmastercraft
09-17-2009, 11:53 PM
First I would try to be sure its a fuel starvation problem by running it at WOT until it dies. Then quickly open the motor cover, remove the spark arrestor and look down the carb (have a small flashlight handy as opposed to a zippo) to see how much if any fuel is present. Pay special attention to the secondary side, as this sounds like it could be your secondary diaphragm is ruptured and not allowing the secondaries to open.

It could also be a fuel delivery issue but that is a little more work to diagnose as you would need to plumb in a fuel pressure gauge so you could read it while running.

Another possibility is your power valve is not opening and needs to be replaced. Usually these fail and dump too much fuel, but they can fail to open as well.

You should take a look at your plugs. They may tell you something about the running condition as well.

Often times these problems are remedied by generically rebuilding the carb, but if it is a bad secondary diaphragm, you can do the work by merely taking the flame arrestor off to access the diaphragm.

Good luck and keep us posted.

steve
09-18-2009, 09:10 AM
Thanks for the help. After doing some more research I just need to verify.
Does the Parker Racor 110 have a replaceable filter inside?
I am the original owner of the boat and did not know there was a filter inside of this.
It has never been changed since 1988. I also have the original fan belt on it, still in excellent shape no cracks, go figure….

steve
09-18-2009, 09:17 AM
Thanks for the help. After doing some more research I just need to verify.
Does the Parker Racor 110 have a replaceable filter inside?
I am the original owner of the boat and did not know there was a filter inside of this.
It has never been changed since 1988. I also have the original fan belt on it, still in excellent shape no cracks, go figure….