Johnson 25hp. Possible Fuel Pump/Carb Issues? NEED HELP!!!

[GMLSX]

Let me start off by saying Hello! I'm new here, and have a feeling I will be back often to get this motor back to everyday running shape. Thanks in advance for any input ya'll have!

I have a 1977 Johnson 25hp (somehow has an Evinrude lid), model # 25R77S.

I ordered a new fuel filter cap kit, cap, o-rings, and replaced the old style. The o-ring doesn't seem like it fits correctly, and is too large so it's on its way back to Crowley Marine and I have ordered a new kit to see if it's a poor fit as well.

I have replaced the fuel line from the connector to the fuel pump, and my tank fuel line and bubble as well.

The motor runs out of fuel and dies. The throttle has no revs in neutral, and the bubble doesn't keep pressure after it dies. I can restart it after I pump the bubble, and it does the same thing. No throttle response at all upon twist, and just dies again.

Does the carb need rebuilt, or has the fuel pump finally failed and need replaced? Any input would be greatly appreciated! I am trying to deter myself from order the NEW 20hp Tohatsu I've been looking at lately...

Thanks everyone!

 

[racerone]

Start with a compression test.---Next is a check to make sure you have spark that will jump a gap of 5/16" on both leads.

 

[boobie]

Sounds like a bad fuel pump.

 

[pn]

if you got the money just buy the tohatsu.

 

[F_R]

Any leak anywhere between the fuel level in the tank and fuel pump will admit air and make it run out of gas. But I think you have more trouble than that. I suspect it is running on one cylinder, since you say it has no RPM in neutral. That generally means an ignition problem, but could be a compression problem on the missing cylinder or a ruptured fuel pump diaphragm. Or a bad spark plug. The carburetor would be the least suspect in my mind.

So, as you can see, it is difficult to diagnose from a distance. You will have to do some on-site troubleshooting.

New Tohatsu???? If you do that, drive by my house at midnight and dump the Johnson in my front yard.

 

[SparkieBoat]

lol FR,,,, do not litter my yard with that old junk... LOL

 

[GMLSX]

What is the plug gap for this year model? The ones in it were about 35 and the ones I bought (NGK) were pre-gapped at 28.

 

[racerone]

Plug gap is not that critical.----It will run fine at 0.035" and it will run fine at 0,028"

 

[GMLSX]

Thanks. I'm off tomorrow and I'll post back with any finds I have. Thanks everyone for the replies!

 

[GMLSX]

Okay, had a moment outside...it'll start and run, but the only throttle response I get it is when the choke stays pulled. Once it goes in it dies out. The choke didn't give me the rpms on throttle every time, but it definitely made a difference. Going to get a compression set in a moment to check it again. It was 110psi a month ago when I got the outabord.

 

[GMLSX]

Checked psi at just over 100 on both cylinders. Is this worth putting a little money into, or is it going downhill? It ran great when I got it. Just don't wanna dump money if it won't last another year.

 

[racerone]

Having to use the choke points at carburetor issues.---And check for spark on both leads.--Good spark will jump a gap of 3/8" or more.

 

[GMLSX]

I already ordered a rebuild kit for the carb. Hoping that'll solve the issue. A few friends want the motor but I want to get it running before selling it. I ordered the Tohatsu last night

 

[racerone]

If you can solve it with $$$$$$$ you do not have any problems.

 

[GMLSX]

If you can solve it with $$$$$$$ you do not have any problems.

I solved it with $$$ because I don't want to be stranded when I do take Her father fishing with me. The 25 Will go to a friend but not until it runs like it was when I first got it.