1971 202hb 20hp fuel pump help

[grizzrider09]

Alright guys it's time for the experts again. My motor cranks, runs, idles, shifts, and performs like a new one. The carb is CLEAN! My problem is that while out on the lake you give it full throttle it opens up and screams across the lake for all of 30 seconds an dies. If you squeeze the bulb she picks back up. Now I have a new fuel pump and have been through this a 1000 times. If you shorten the hose from the tank it will perform magically. Only problem is I have shortened it so much now I can go any shorter. I replaced all connectors to new johnson style connectors. Is there anything I can do to make the fuel pump stronger and hold more pressure. Oh and the tank and lines are new to with no leaks.

 

[pnwboat]

Re: 1971 202hb 20hp fuel pump help

Have you tried increasing the diameter of the hose between the tank and motor?

 

[grizzrider09]

Re: 1971 202hb 20hp fuel pump help

The hose now is a 3/8. If I went bigger I don't know that it would fit the barbs. I had thought about going smaller though with the thought that it might constrict the air space for lack of a better word. I'm just tired of it doing the same old thing time and time again

 

[kfa4303]

Re: 1971 202hb 20hp fuel pump help

Hi grizz. The fact that the motor picks up when you manually prime the bulb means you have an issue with the fuel pump. I have a '66 20hp and my fuel line is over 6ft. long and it works fine. I just fired her up today, as a matter of fact. I suspect either the pump is bad (hole in the diaphragm perhaps?), or there is an air leak somewhere. Here are some handy links.

Maintaining Johnson E & FD Serie
http://www.*****************/parts/johnson-evinrude-parts.php?year=1971&hp=20&model=20R71S
Rebuilding the OMC Fuel Pump

 

[Nordin]

Re: 1971 202hb 20hp fuel pump help

Check the float level in the carb. If the float level is low, it will starve at higher rpm and picks up when you prime the bulb.
Level should be parallell with the casting when you turn the carb upside down.

 

[pnwboat]

Re: 1971 202hb 20hp fuel pump help

I'm not familiar with the fuel pump that is on your motor, but there are usually some one way check valves. I know in the later model Force motors, once in a while the spring loaded disk in the check valve will stick causing fuel delivery issues.

 

[grizzrider09]

Re: 1971 202hb 20hp fuel pump help

Guys I appreciate the help. I will try all of the above. But it still doesn't make sense to me that by shortening the fuel hose the problem goes away. I have rebuilt the fuel pump 4 times now so the diaphragm is good. It would have to be the actual metal pieces. As far as air leaking goes it's a new tank lines and fittings. I'm lost but will try it all again

 

[kfa4303]

Re: 1971 202hb 20hp fuel pump help

The fact that it seems to work with a shorter hose suggests a weak draw from the fuel pump. If the pump is the rectangular model with one pointed end, then I don't think it can be rebuilt. Although the small, square pumps used on the 18hp and lower hp models can be rebuilt, albeit with varying degrees of success. It save a bit of time and energy to simply find a replacement pump. When working properly it should easily be able to draw fuel from a tank in the bow. The brand new replacement OMC pumps aren't cheap (+$80), but you can probably find a good used on online and/or use an alternate brand like Mikuni or Briggs & Stratton, if need be.

 

[Nordin]

Re: 1971 202hb 20hp fuel pump help

kfa4303 this is a West Bend/Chrysler engine and the fuelpump is way different from the OMC brand.
The pumpmounting to the powerhead on WB/Chrysler is different and the surface is machined at the powerhead , the surface is a part of the pump..
OMC has only a hole with a thick gasket and two screws to the powerhead where you mount the pump.

 

[grizzrider09]

Re: 1971 202hb 20hp fuel pump help

Where can I find a used one to replace the entire pump. That's what I would rather do to.

 

[Nordin]

Re: 1971 202hb 20hp fuel pump help

Try Ebay, Craiglist or Franzmarine. He has everything for Chrysler/Force OB that is available. He can be expensive BUT # one in servicemind.