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Philip
06-28-2010, 07:51 PM
Hi!

I have a MC Prostar 190 -89 Ford 351 Indmar converted with fuel torrent problems.

First of all, I donít know anything at all about engines. But after two summers with problem Ill do my best to explain the situation.

Earlier owner hade installed a fuel hose with a primer pump. Shown on the picture below:

http://www.rchobbies.com.au/store/images/ttPD1594.jpg

I must pump up the fuel 2-3 times before I can start the engine. If Iím not pumping I canít start the engine at all, no matter what I do with the throttle.

There is no gas spraying into the carp when I push the throttle. Is there a problem with the accelerator pump perhaps?

When the engine is running its going in waves, up and down in rpm. Like itís not sufficient with gas or as there is air in the fuel system. When the engine is running I can pump some gas by hand and the engine runs smooth.

Sometimes when I run the boat over 2500 rpm it just dies. But only sometimes (one time is one stop to much). Again, like it donít get any fuel.

This is what I have done so far:

Checked that the air from the tank to the hull is ok. Everything seems just fine. Is there suppose to be an air pump or something there? There are no air pump installed but there is air from the backside of the hull to the tank, for sure.

Checked that there is free torrent of gas in the tank.

Uninstalled the back valve. Do you know what I mean? I donít know the right word in English.

Changed the fuel hose from the tank to a brand new marine water separator.

Changed the fuel hose with a primer to the mechanical fuel pump.

Changed the fuel hose from the pump to the carburetor.

Cleaned the carburetor and changed all the gaskets off course.

Tried with a marine fitted 12 volt fuel pump up to 7 bar (worked like krap), and uninstalled it.

I have also changed all the sparking plugs and wires.

I donít even mention that I have already changed the oil and filters properly. :)

After this changes the boat drives better on low rpm but still knocking and is still not pure. The same problem with high rpm as I earlier mention.

The next step is to demount the fuel pump and check for problems with the pump and/or the camshaft that pushes the fuel pump. But I am most worried about the problem that there are no flush in the carburetor when pulling the throttle. Do you have any ideas?
The summer in Sweden is short so I rely hope you can help me out :)

Regards
Philip

Napagary
06-28-2010, 08:54 PM
Hello - welcome to this site - I hope we can help you, you are quite a distance away!
I see you have installed a water separator. It seems your problems may be in that area?
Have you drained the tank or checked for obstructions/dirt within the tank?
Next I'd check the mechanical pump. These pumps are not very good at sucking fuel thru an obstruction or from a great distance.

thatsmrmastercraft
06-29-2010, 12:11 AM
Welcome to Team Talk. I'm sure we can help you to resolve the problem and get you back on the water.

If the accelerator pump isn't spraying fuel when you work the throttle, and you have to pump the bulb to get fuel into the carb to get it started, I think the problem is likely the needle and seat in the carburetor is allowing the fuel to leak back out of the carb. You could also have a bad or incorrectly adjusted accelerator pump. I would also guess that the fuel pump is needing to be replaced.

I would be inclined to rebuild the carburetor and replace the fuel pump.