1991 Johnson 175hp J175EXEIS Will only start and run using primer bulb

WetDreamTX

Recruit
Joined
Sep 6, 2022
Messages
4
My 91 johnson 175 will only start and run on primer bulb, but the oil side of the VRO is pumping oil.
-Is it a fuel pump side VRO problem?
-Can I rebuild it if need be, or did I read correctly no rebuild kits available pre-1998
 

kbait

Commander
Joined
Nov 13, 2007
Messages
2,462
Could be faulty fuel pump, could be a leak in fuel lines/connectors. To test, pump primer bulb until firm and keep squeezing with moderate pressure. Look for fuel leaks from primer bulb to pump and pump to carbs. If no leaks, those lines are sealed. Still could be a leak between primer bulb and fuel level in tank.. you could test by replacing the fuel line between primer bulb and engine-side coupler on fuel line with clear poly hose and running engine. Any air in clear tube after initial priming will be a leak.
Good luck!
 

WetDreamTX

Recruit
Joined
Sep 6, 2022
Messages
4
Could be faulty fuel pump, could be a leak in fuel lines/connectors. To test, pump primer bulb until firm and keep squeezing with moderate pressure. Look for fuel leaks from primer bulb to pump and pump to carbs. If no leaks, those lines are sealed. Still could be a leak between primer bulb and fuel level in tank.. you could test by replacing the fuel line between primer bulb and engine-side coupler on fuel line with clear poly hose and running engine. Any air in clear tube after initial priming will be a leak.
Good luck!
This is my first outboard I've ever worked on and now something makes sense. The O-rings are bad on each top carb (fuel rail?)- the injector type with 2 small o-rings supplying the carb. So what your saying is that the obvious leak from the fuel rail? Is keeping the air pressure from moving the fuel pump diaphragm? Couple bucks on o-rings sounds better than a 500$ VRO lol. Thank you
 

flyingscott

Fleet Admiral
Joined
Apr 8, 2014
Messages
8,095
O rings being bad makes no sense at all. If the orings were bad and the fuel pump good gas would be shooting everywhere. What is your compression? Do you have spark on all cylinders? The fact it only runs if you pump the ball points directly to the fuel pump. Fuel side rebuild kits are around $160. Does the motor keep running if you press the key for the primer.
 
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