Video: Johnson 150 dies at WOT

[shane772]

New to me boat. I changed the impeller and gear oil and took it out. It ran amazing. I took it to the lake and ran 30 minutes up and 30 back. No problems at all.

Next trip out, it wouldn't get on plane. So I checked compression; all 6 cylinders were @ 100psi. Changed plugs, Champion QL78YC, changed fuel line and bulb from transom to motor. Went out and it will get on plane easily but now dies at wide open throttle as in the video. Once it dies, I squeezed the bulb and it would start back up and do the same thing. I assume I'm starving for fuel??? If I can get a helper I'll take it out and have them squeeze bulb and see what happens.

1991 Johnson 150 Faststrike
model: VJ150GLEIS

 

[jakedaawg]

You already have enough information. Continuing to do that, whether squeezing the bulb or not, will make a lean condition and do damage not easily remedied.

replace vro or attempt to rebuild fuel side. The fuel side can be inspected and you will probably find a ruptured diaphragm. Assuming you have good fuel line and bulb and no fuel restriction. Alarm didn't sound so probably not a fuel restriction.

 

[shane772]

Thank you for the response. I will start a new thread for the fuel pump side questions.

 

[shane772]

So I disassembled and inspected vro pump. Internals look brand new to me. Definitely no cracks/tears etc in the diaphragm. Do you think I should just replace pump at this point? I fully expected to see a glaring problem once I got it opened up and that didn't happen.

Also, the oil pump wires were still hooked up. Should they be? I don't think it has anything to do with this issue just curious.

 

[Bosunsmate]

Those pumps are expensive. Like you say Id get a mate to prime the bulb to confirm thats the issue and if it is take it apart bit by bit and document it on here and someone will pick up where its broken.
It does seem like fuel to me but ive being wrong more than once.

 

[Bosunsmate]

yes wires should be hooked up.
Also check the primer bulb stays hard for a while with engine off, it may be sucking air up from a leak back towards the tank too so check when you prime it that it fills the lines and float bowls quickly (slowly indicates an air leak)

 

[Chris1956]

Gee, check your fuel filters. A lot of those motors have a screen under the airbox. If they clog, the motor will starve.

If you are running a water separator, change it.

 

[SweetD]

If it is your fuel pump/VRO, there is a good alternative to purchasing an expensive new replacement VRO/fuel pump. They make a fuel-only pump that will bolt on to where your existing VRO/fuel pump is now. If you go this route, you would then have to pre-mix your fuel/oil going forward. You can find your compatible pump from this chart here:

https://www.offshoremarineparts.com/vrorep_chart

Just another option to look at -

 

[racerone]

Run with a timing light to see if ignition may be failing / intermittent.------Also run with a portable fuel tank and hose as a test.----Check fuel for water !

 

[shane772]

Update: I bought the Off shore fuel pump as I was CONFIDENT the problem was fuel. I installed new fuel pump and went out again. Came back with a new problem, LOL. Motor acted like it was hitting the rev limiter once on plane. Checked the service manual and suspected the power pack. My uncle talked me into taking it to the shop, seeing how I just spent $200 for fuel pump and didn't fix it. Got the call today, it needs a power pack! 3 weeks in the shop to find out but at least it will be fixed and I can get in some fall fishing. Thanks for all the replies/help.