Logo
FULL SITE MENU

Identifying fuel supply problem

P

Philfry159

New member
I'm chasing a fuel gremlin in my Johnson 40 HP VRO - Model J40ELCDE outboard motor. I prime the engine and it starts immediately. I put it in drive in low speed and it'll go for a little bit before stalling. When I put it in full speed it lacks power and will occasionally rev and give more power. If I continue to squeeze the primer bulb while the engine is running it has no issues. I'm thinking its a problem with the fuel pump/diaphragm, however, when I removed it and opened it up I didn't see any visual signs of issues with it. I'm going to try and replace the entire pump.

So far I've done the following which has not corrected the issue.

- Bypassed the fuel filter to check if its a issue with the filter being clogged.
- Replaced the fuel with new fuel to make sure its not a issue with the fuel.
- Removed the quick connects to make sure its not a issue with loss through the quick connects.

If replacing the fuel pump/diaphragm doesn't work I'm going to replace all the fuel lines. Any other thoughts or suggestions on what this might be.
 
I am not there to see / hear / feel your engine.----Is this something that developed suddenly ?------How did it run last year ?-----Checked fuel pick-up tube INSIDE your fuel tank ?----The fuel pump is driven by PRESSURE pulses from the crankcase.----What fuel pump is on this motor and is it original ?-----Have you done a compression test on this motor ?---A new VRO pump would be expensive.
 
racerone said:
I am not there to see / hear / feel your engine.----Is this something that developed suddenly ?------How did it run last year ?-----Checked fuel pick-up tube INSIDE your fuel tank ?----The fuel pump is driven by PRESSURE pulses from the crankcase.----What fuel pump is on this motor and is it original ?-----Have you done a compression test on this motor ?---A new VRO pump would be expensive.
Click to expand...

It ran fine last year and its become a sudden issue this year. I have two 6.6 gal tanks and I've tried the engine with both tanks. I assumed that both fuel pick up tubes weren't clogged. I'll give both of them a check. The pump assembly is a model 0395713 unit and I believe its original to the motor.
I have not done a compressor test on the motor and will try that as well.
 
looks like to me that it has a standard fuel pump ,I would be checking the pickup in the portable tank(filter)
Disconnect the hose at the outboard and pump the bulb into a container and see if there is any blockage from the tank to the outboard.Eliminate the areas 1 by 1.
 
Back
Top