1975 85 HP Jphnson V4 - Fuel Problem

[wbentell]

My motor stopped running and I checked the outflow of fuel from the pump to the carbs. No output. I bought a new fuel pump. Same result. When I disconnect the two outflow lines to the carb and crank the engine - no gas coming out. What am I missing? I have gas to the fuel pump.<br />Thanks for any help

 

[Joe Reeves]

Re: 1975 85 HP Jphnson V4 - Fuel Problem

Wbentell..... When pumping the fuel primer bulb (with the hoses leading to the carbs being disconnected), fuel should shoot out of those hoses. If not, you've got the fuel pump lines reversed.<br /><br />If fuel does shoot out of those hoses, but will not pump out when the engine is cranked over (assuming that the new fuel pump is okay), there would have to be a crankcase pressure/vacuum problem.<br /><br />This could be caused by a broken leaf plate and could be checked by removing the carburetor face plate, then cranking the engine over. If a leaf plate was broken, fuel and pressure would be blown out the carb throat every time that particular piston went through its down stroke.<br /><br />Crankcase pressure coulld also be lost due to a blown piston, a cracked block etc, but hopefully that's not the case. Let us know what you find.

 

[wbentel]

Re: 1975 85 HP Jphnson V4 - Fuel Problem

At first the pump was not pumping fuel when cranking. It appears to be pumping now. Still having problems as to starting. May be slow crank rate. Now charging battery. <br />what are the two exit hoses ( I know one goes to carb. where does the other go and what does it do?)

 

[Joe Reeves]

Re: 1975 85 HP Jphnson V4 - Fuel Problem

Wbentell.... A fuel pump for a 1975 85hp Johnson will have three hose connections.<br /><br />1 - Incoming fuel to the movable plastic filter assy on the front of the pump.<br /><br />2 - Outgoing fuel from the middle plastic connector (tube) to the carburetor(s).<br /><br />3 - Pump operating hose (pressure/vacuum) to the metal connector (tube) of the fuel pump. The other end of the hose being connected to the crankcase pressure fitting.<br /><br />If your engine uses a fuel pump that operates directly off of the crankcase (block) via a hole that's located between the two pump mounting screws, and uses a small gasket between the pump and the crankcase, it sounds to me like you might have the wrong fuel pump installed.<br /><br />Get back to me with the model number of your engine and I'll pinpoint what you have and what you need.

 

[leeray]

Re: 1975 85 HP Jphnson V4 - Fuel Problem

do you have gas to your fuel pump from the tank?

 

[wbentel]

Re: 1975 85 HP Jphnson V4 - Fuel Problem

thanks for responding. I have an 85ESL75 Model. The pump I used as a replacement is a pn# 438559, which is the same type I had on the motor. The only diffence being the top bolt that was attached to the block did not line up with the new hole on the pump. They had a shorter bolt to seal the pump. Also I put the wrong hose on the vacuum hose and pumped fuel into it. I realized my error when the bulb wouldnt get hard. Did I do any damage? Also would a weak battery diminish the spark on the cranking. Thanks for your help. Wayne