25 HP 1989 Johnson - Will It Run With Primer Disconnected?

[Josey Wales]

My 25HP bogs down and quits about 70% of the time I punch the throttle. Then suddenly it will take off and run at WOT just fine. I stop and fish. Start it, punch throttle and it kills...repeat 5 or 6 times and suddenly it takes off fine.

I rebuilt carb, fuel pump is fine, now I suspect the manual prime unit. I notice sometimes it is under pressure (I can feel pressure when I push it in / out) and sometimes it is totally void of pressure when I push it in/out. It's a network of tubes goin to the carb. I see a replacement is $80. Since I never need to prime anyways, can I just cut the tubes, jam a couple golf tees in them to seal them off and be on my merry way? Or will this not work? It has a choke so I dont really need the primer for starting purposes.

Tnx, JW

 

[Willyclay]

Re: 25 HP 1989 Johnson - Can I nuke the primer?

Re: 25 HP 1989 Johnson - Can I nuke the primer?

Since I never need to prime anyways,

How do you get it started without using the primer? I would NOT disable the primer since it is an essential part of the design. I read your original thread and see this has been going on for over a year. I agree with your opinion then that a clogged high-speed jet would not act like this; intermittantly. My first though was the carburetor float/neeedle valve assembly. Did it get replaced when you rebuilt the carb? One of my buds has a 1987 Johnson 25 and it was acting very much like yours. The only thing we found wrong was a missing clamp on one of the fuel lines. We replaced it and the motor ran perfectly. It's usually the simple stuff that trips us up. Hang in there and you will whip it. Good luck!

 

[Josey Wales]

Re: 25 HP 1989 Johnson - Can I nuke the primer?

Re: 25 HP 1989 Johnson - Can I nuke the primer?

How do you get it started without using the primer? I would NOT disable the primer since it is an essential part of the design. I read your original thread and see this has been going on for over a year. I agree with your opinion then that a clogged high-speed jet would not act like this; intermittantly. My first though was the carburetor float/neeedle valve assembly. Did it get replaced when you rebuilt the carb? One of my buds has a 1987 Johnson 25 and it was acting very much like yours. The only thing we found wrong was a missing clamp on one of the fuel lines. We replaced it and the motor ran perfectly. It's usually the simple stuff that trips us up. Hang in there and you will whip it. Good luck!

Thanks for the response!

It's always just fired right up when I choke it. Yes, the needle/float valve's were replaced. This weekend I was puttering along for about 5 minutes. It ran fine. I hammered it....it takes off almost to plane, then sputters and quits. It did this 5-6 times. It doesn't always quit. If I let go of throttle when I hear it start to sputter it will return to idle without quitting.

When it did quit on the 6th or so time I pulled the primer and there was zero pressure. I pumped the primer lever about 8 times until I felt pressure. Then when I took off it worked fine, full throttle forever. Until I stopped to fish, cut motor, then when I left the spot I was back to the same song and dance.

If air is getting into the priming unit...could that mean a bad seal at the gas tank?

 

[kbait]

Re: 25 HP 1989 Johnson - Will It Run With Primer Disconnected?

Check your lines. If they're all good, there's a couple o-rings in the primer assembly that may be bad. You can't choke to start.. pulling out the knob gives the carb throat a shot of fuel. Pumping it to get pressure sounds wrong, but if it helps, you must have air intrusion somewhere I would think, and running a low bowl of fuel when it fails..

 

[Willyclay]

Re: 25 HP 1989 Johnson - Will It Run With Primer Disconnected?

It has a choke so I dont really need the primer for starting purposes. Tnx, JW

I'm an old guy and get confused easily so bear with me. Don't believe your motor has a choke AND a primer. It should only be one or the other. Your description of a manual primer is consistent with what the BRP parts website shows for model number J25TELCCA. FYI, that is a 1988 model, not 1989, but since they are identical the discussion is still valid.

http://epc.brp.com/Index.aspx?lang=E&s1=bf2597b9-1f09-4473-9fb4-65c2333ac9a0

Looking at the schematic of the primer system reminded me that the problem on my bud's motor was with one of the primer system hoses and OMC used nylon zip-ties for clamps. It seems that we all; you, me and kbait, think that your problem is in the primer system. Just trying to help but you are they guy with hands and eyes on the motor. Good luck!

 

[Josey Wales]

Re: 25 HP 1989 Johnson - Will It Run With Primer Disconnected?

You're right...it just has the primer..no choke.

Problem is getting worse. Can't even go full throttle now.

 

[Willyclay]

Re: 25 HP 1989 Johnson - Will It Run With Primer Disconnected?

Bummer! If you think you can get it started without the primer, why not go ahead with your earlier idea and plug all the hoses to the primer. Let us know what happens. Good luck!

EDIT: Can you borrow a bud's fuel hose from a good running motor and try it on your motor? This may be as simple as bad O-rings in the fuel hose connectors. Just another thought!