1991 Force 35 Fuel Pump - doesn't match parts list

[Evinrude_NooB]

Hello Everyone and thank you for reading my thread.

I bought a used 1991 Force 35 with the hope of fixing it up.

The previous own says that the fuel pump started leaking after he added some bad gas in the tank and then subsequently tried to rebuild the pump.

Before buying the motor, he did start it for me, but only for a few seconds because the motor was dry.

Model is 358F91B
Serial is 021357

I took the pump out to see if anything was cracked/broken and nothing was. I went to USBoatWorks.com to see the parts diagram and parts list and noticed that the part I have does not match with the parts list. Specifically, part #17, SPACER, FUEL PUMP on the parts list has a male nipple and the one I took off the motor does not. I also have a Force 50 and the pump on that motor looks like the one on the parts list. That nipple on my 50 HP attaches to the motor. Does that provide the vacuum for the pump?

Parts list Link to OEM parts: OEM Parts

I also noticed that part #16 might be missing on my pump. I see the FUEL PUMP DIAPHRAGM, but don't really see one on my motor. Maybe that's the reason the pump is leaking.

Can anyone provide any insight on the the differences on what I have and what's in the diagram?

One other question. Where is the thermostat in this motor? I took off thermostat cover, but there is no thermostat inside. The parts diagram doesn't list one either. Very odd.

Thank you.
Thank you.

 

[Frank Acampora]

Re: 1991 Force 35 Fuel Pump - doesn't match parts list

That is similar to the old two stage pump that has been around since Chrysler. Your pump should have a diaphragm and a gasket. The back of the first stage should have a hole in it. This hole should seat against a gasket on the bypass cover.
Order of assembly is spacer plate, gasket, diaphragm, and top cover. The black plastic cover is the inlet and the other nipple is out to carb.

I can only guess that since the 35 uses so little fuel compared to the bigger engines (120, 125) on which this pump is used, the second stage (smaller chamber) is not necessary, thus they saved money on two 90 degree nipples and a length of tubing. If you look inside the smaller chamber, they may have also left out the button valve.

HOWEVER: Some of these pumps have the impulse fitting in the bypass cover with a passage to the second stage. Is yours like that?

At any rate, the gasket and dia[pragm are all the same.

 

[Evinrude_NooB]

Re: 1991 Force 35 Fuel Pump - doesn't match parts list

This is what it looks like apart.

 

[Evinrude_NooB]

Re: 1991 Force 35 Fuel Pump - doesn't match parts list

Does anyone know where the thermostat is on the Force 35? I took the housing off but no thermostat inside.

 

[roscoe]

Re: 1991 Force 35 Fuel Pump - doesn't match parts list

The late 80's thru '91 35 hp didn't have a thermostat.

 

[Frank Acampora]

Re: 1991 Force 35 Fuel Pump - doesn't match parts list

Ah-Hah! I see two impulse holes in the base casting. By any chance, does that pump mount vertically instead of horizontally? Does it use O-rings to seal it to the crankcase?

Old Chryslers used a pump very much like that which spanned two bypass passages, being mounted vertically. Each stage took impulse and vacuum from a cylinder with no hoses used.

Again, the diaphragm and gasket are standard and will fit any pump. But, that diaphragm and gasket look decent and serviceable.

 

[Evinrude_NooB]

Re: 1991 Force 35 Fuel Pump - doesn't match parts list

Good to know because I was looking all over for it and also through the parts list. Guess it's one less thing to worry about.

Thank you.

The late 80's thru '91 35 hp didn't have a thermostat.

 

[Evinrude_NooB]

Re: 1991 Force 35 Fuel Pump - doesn't match parts list

Yes, Frank. It does mount vertically. It's funny that you asked about the o-rings. I don't see any and didn't see any when I took it out. On the parts list, I don't see any between the pump and the crankcase either. Should there be one?

As for the diaphragm, it's still relatively new because the previous owner just replaced it. However, he failed to install the gasket. One of the reason he told me for getting rid of the motor was that the pump was leaking. So my guess would be it's leaking because the gasket is missing and the spacer couldn't get a good seal.

It makes very much sense that there would be o-rings between the pump and the crankcase. I guess when I'm at Home Depot tomorrow looking for some new hose bibs, I'll also look for a couple of o-rings that would fit this.

Ah-Hah! I see two impulse holes in the base casting. By any chance, does that pump mount vertically instead of horizontally? Does it use O-rings to seal it to the crankcase?

Old Chryslers used a pump very much like that which spanned two bypass passages, being mounted vertically. Each stage took impulse and vacuum from a cylinder with no hoses used.

Again, the diaphragm and gasket are standard and will fit any pump. But, that diaphragm and gasket look decent and serviceable.

 

[Frank Acampora]

Re: 1991 Force 35 Fuel Pump - doesn't match parts list

You just HAD to make me go down into the garage to look, didn't you? LOL

Yeah! It peaked my curiosity so I did go look: On my old 2 cylinder 60 HP Chrysler, the pump is plain while the block has a small O-ring set in a groove at each port. Now, that doesn't mean yours will also. It may just have a long gasket to seal the back of the pump body. In fact, if your block does not have provision for the O-rings, it probably will be better if you just make a simple gasket from 1/32 gasket paper--available at almost any auto store.

At that parts site, look at 1980 55 Force. It shows your pump.

 

[Evinrude_NooB]

Re: 1991 Force 35 Fuel Pump - doesn't match parts list

It looks like there's groves at each port for o-rings. I'll try to see what I can find that would fit it.

 

[Frank Acampora]

Re: 1991 Force 35 Fuel Pump - doesn't match parts list

No, those grooves are meant to "bite" into a gasket. Look at the intake manifold at the carb flange and bypass ports openings. There is a cast-in groove very similar to help seal the gasket.

 

[Evinrude_NooB]

Re: 1991 Force 35 Fuel Pump - doesn't match parts list

Thank you for setting me straight about the grooves.