fuel flow problem

rsw21282

Petty Officer 2nd Class
Joined
Jan 25, 2009
Messages
122
i have a 88 85hp force. i took it out the other day and it started giving me problems, so checked the inline fuel filter(glass) and its getting starved of fuel. it would want to die if i throttled up to long but if i pump the primer ball while i do this it would keep going, so i have obviously taken place of the fuel pump. so got home and took the pump appart and looking at it not to much can go wrong here am i right? the diaphragm i just replaced few weeks ago and it was fine, all passages and filter clean, button valves working(or dont appear to be broken, move when pressed), the orfice from the eng. to the pump is clean(that just moves the diaphragm when crankcase press changes from piston movement right?) so now the question is what else could it be? how strong is the fuel pump? if i am pressing the primer bulb could it be that the check valve is bad and the pump not strong enough to overcome at high rpm? also the gas tank has good ventilation so no vapor lock there. i did disconnect the primer bulb and a little pump shot fuel out fine so any suggestions?
 

1fullforce

Seaman
Joined
Jul 6, 2007
Messages
51
Re: fuel flow problem

maybe the primer bulb is bad, after you prime it before starting motor its suppose to stay hard not soft where u can keep on priming it. on the fuel pump did you clean the wire screen filter on the sediment bowl? disconnect the fuel pump hose going to the carbs put the end of the hose in a container ,prime the bulb and check the flow of fuel.
 

Frank Acampora

Supreme Mariner
Joined
Jan 19, 2007
Messages
12,004
Re: fuel flow problem

I never did like the glass in-line fuel filters. The fuel passages are small and easily clogged. I would disassemble the filter and see if there is any varnish or junk restricting where the fuel flows in from the pump. The one I do have has had the threaded inlet passage enlarged with a Dremel.

But basically, I have gotten away from them. I now use a nice plastic see-through unit with a fine screen: Purolator F50153--about 7 bucks.

You can get other plasic filters for as low as 3 bucks, and there is nothing wrong with them but I just like the Purolator because of its size and shape.
 

john from md

Commander
Joined
Apr 13, 2008
Messages
2,184
Re: fuel flow problem

RSW,

Does your engine die and then start up easily? Can you keep it running by pumping the ball? Is the ball soft after the engine cuts out? Will it run at higher power but shut off at low power?

If the answer to these questions is yes, then the check valves in your pump are sticking. To verify this, take the pump housing off and remove the check valve with the two screws. Slowly push on it a few times and see if you can get it to stick. There is one other check valve that you can press on , the other is pointing the wrong way.

You have to look closely to catch them sticking. If you have an amber colored plastic, then they are probably original. I believe the alcohol in the gas causes these to expand and start to stick.

These can be bought from Mercruiser for $5 each.

Regards,

John
 

rsw21282

Petty Officer 2nd Class
Joined
Jan 25, 2009
Messages
122
Re: fuel flow problem

ok guys figured out my fuel problem. took off a fuel line after primer bulb and had some kind of lining clogged in it, put the aircomp to it and blew out about a golf ball mass full of crap and now fuel flows so check lines!
 
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