1988 Johnson 120 sluggish *Updated*

[Jake Blood]

I havea 1988 Johnson 120... it is a VRO, but the VRO is diabled. This boat was running great, but then one trip out it started running sluggish.. it would get up on plane, then nearly stop, then go, then go at low speed ( while still full throttle ), then high speed.. like if you pinched the fuel line, then released, pinched it, then released.. weird. Then after riding for awhile it would run great... Well this last time out, it did the same thing, now all it does is putt along.. at full throttle. I also noticed t one time the gas can.. one of those red outboard gas cans, started getting the air sucke out of it.. it was compressing.. I opened the vent and it went back to normal and did not happen again...

I did check the plugs, and they looked fine, though I may need to have them gapped again?

I took out the high speed jets and cleaned.. those were fine.. are there others I should clean?

The fuel filter was slightly dirty, but even when I bypassed it, it didn't run any better...

Any thougts? I was hoping to go out tomorrow.. I hate to disappoint the boys..

Thank you for any suggestions.. I got all night and I am motivated. Thank you.

 

[Daviet]

Re: 1988 Johnson 120 sluggish

Re: 1988 Johnson 120 sluggish

I think you ansewered your own question. It sounds like you for got to open your tank vent. With the vent closed the fuel pump will suck a vacume and cannot suck fuel. I would try running your boat again with the tank vented and see how it runs.

 

[Jake Blood]

Re: 1988 Johnson 120 sluggish

Re: 1988 Johnson 120 sluggish

Well I did open the vent.. its still not right. I was happy when I saw it closed.. thought to myself.. theres the problem... easy fix,, not my luck...

 

[Daviet]

Re: 1988 Johnson 120 sluggish

Re: 1988 Johnson 120 sluggish

A couple of thoughts, you might try pumping the primer bulb when it is acting up, if it picks up by pumping the bulb, you have a fuel pump problem. If that doesn't help, have some one run the boat, use an inductive timing nlight and check the spark on each cylinder.

 

[Jake Blood]

Re: 1988 Johnson 120 sluggish

Re: 1988 Johnson 120 sluggish

OK.. Just took the carb cover off.. gas.. lots of it went all over the place... soon as I tilted the engine down I saw it leaking down the engine.. So.. that is the reason for the sluggish operation.. but what caused the gas to build up like that?

Float stuck? Clogged jet? Anyway to tell without rebuilding the whole thing? I am thinking that it probably needs to be rebuilt, but I dont have the time or money right now...

Anything I can check... clean out?

 

[Daviet]

Re: 1988 Johnson 120 sluggish

Re: 1988 Johnson 120 sluggish

Pump the primer bulb and see if gas comes out of carbs, if so the needle and seat is not closing properly. Could be float or trash in the needle and seat . Either way the carb will have to come off.

Look on the front of your carbs and there is a 7/16 plug on the bottom of the bowel, behind that plug is where your high speed jet is located. It takes a special tool to remove the jet, you can take a flat blade screwdriver that will just fit in the hole, remove jet, it unscrews, and see if it is pluged. If you can't get the jet out take a piece of fine , stiff wire and try to run it in and out of the jet to make sure it is clear. The jet is in about 1 inch. If cleaning the jet helps, you will need to clean the carbs, may work for a while, but you will have to rebuild the carbs to make it wright.

 

[Jake Blood]

Re: 1988 Johnson 120 sluggish *Updated*

Thanks man... Me and the boys are going to hit the lake tomorrow.. I didn't have a chance to do all of that.. but I will tomorrow when we get back.. I figure for where we are going, I can use the trolling motor with no issue..

I really appreciate the help.. thank you.