Fuel Filter

[Blinkin]

1977 Chrysler 75hp outboard motor (model: 757 HC).

Anybody know a good source for picking up a fuel filter for this motor (part numbers are appreciated)?

 

[Blinkin]

Re: Fuel Filter

I did some google searching as well as searching through the forum here and found it all a bit confusing. Pretty much everybody talks of inline filters. I plan to add an inline filter but there is a filter or maybe a screen (haven't opened it yet) behind a cover on the motor itself. I want to replace that so it is good and clean and then I can buy a handful of cheap inlines to do the dirty work from here on out.

Reading the other threads also brought a little doubt as to my actual problem. I assumed it was fuel the way it was acting and figured a filter would be a cheap and easy place to start.

i took the boat out the other day after some restoration work and everything was working great. Started with fresh tank of fuel, pumped the bulb, little choke and cranked right up. Ran across the lake and trolled around a bit testing out the new troller I just installed and then headed back. This is when I ran into the problem. Running WOT just going along and blah... just acted like it got starved for fuel. Ran ok at low rpm and was ok working back into WOT then blah... once again.

That is why I figured I would start with the fuel filter. Does anybody concur or maybe a second opinion?

Thanks in advance guys!!!

 

[Frank Acampora]

Re: Fuel Filter

Sounds like it is running out of fuel. Several things in addition to a fuel filter could cause this problem. First I will describe the problem: Engine runs fine at high speed then dies. Before it stalls, if you pull it back to idle for a few minutes it will then run fine at high speed for a little while then die--over and over. What is happening is that at low speed the fuel system is able to fill the carbs and supply enough gas to keep them filled. At high speed it does not deliver the amount of fuel used and eventually the carbs run low--engine speed drops and engine may stall. Will restart with choking and run at idle.

You need to start right at the fuel tank. Check to be sure the vent is open or if a built in tank, the vent is clean and clear. If the tank has a strainer, check to see that the strainer is not partially clogged. Next check the fuel line to be sure there are no restrictions (tank is not sitting on it, is it?). Check the quick-connect fuel fitting if it has one. Crud tends to collect behind the check ball in the male fitting. You need to unscrew it to clean behind the ball and internal spring. Check the priming bulb to be sure it passes fuel freely. Check the screen on the fuel pump to be sure it is clean. Remove the top of the pump (six fillister head screws) and check the diaphragm. If it is hard and wrinkled or has perforations of any size, or if it is shedding black particles, replace it and the gasket(3 bucks and 1 1/2 bucks). This is the same part for almost every Force and Chrysler 3 and 4 cylinder engine so you should be able to get it at your Mercury dealer. Ask for say, a 1990 Force 90 hp fuel pump diaphragm and gasket. If not contact franzmarine.com or contact him at The Chrysler Crew.

Since it does get enough gas to start running at full throttle, and does run at full throttle, you probably do not have a carb problem. However, to avoid future problems put a disposable filter in the fuel line BETWEEN the fuel pump and carbs (in case the diaphragm does start shedding). You can buy the chrome and glass one with replaceable screens at Pep Boys, Napa, etc for 11 bucks, or take your choice of the cheap plastic filters at the same stores or Wal-Mart for around 3 bucks. They carry a nice one for Fords at Pep Boys with a 90 degree on one end. It has a fine screen inside instead of a paper filter. I like it. It costs about 6 bucks