98 Fast Strike 115 #4 cylinder washing out.

[bjsmith919]

I thought I had the problem corrected on my 98 Johnson fast strike 115, model #j115glecm, but apparently not. My #4 cylinder is washing out with too much fuel for the plug to spark between 3000rpm and 5000rpm. Was having this problem before but after I rebuilt the carbs, installed new bowls, put new reeds in, replaced fuel hoses from the tank to the engine, and cleaned entire fuel system on the engine the problem went away for 5 outings. Took it out this past Saturday and it started acting up again, really struggling between 3 and 5k, surging and bogging out. Met my local mechanic at the lake yesterday for a run so he could see what it was doing then took it back to his shop for a good look over. He couldn't find anything that would be causing the problem. Pulse limiter checked out, fuel pump is good, no water intruding into the cylinder. For some reason it is just getting way more gas than it should be, not allowing the plug to fire. The plug is getting good strong spark with a spark checker. Also did ignition tests while on the water and everything checked out ok. He has worked on quite a few of these but has never run into this problem before and I'm hoping that someone here may have and will have some insight into what is going on. Any advice given is greatly appreciated.

[316jughead]

Wasn't you original problem getting no fuel to #4? How about compression? Running a cylinder with no fuel can cause serious problems.
Spark plugs Champion QL78YC gap at .030, new or old?

[bjsmith919]

Yes brand new Champion spark plugs. I Thought my problem was no gas but after the mechanic rode in it last night and did his diagnostic tests it turns out that cylinder is getting too much fuel and not allowing the plug to spark.

[bjsmith919]

And yes, that's me. Goes to show what trying to shade tree your stuff will do for you. What has me worried is he says everything seems to be doing what it's supposed to do, just that 1 cylinder. Said he's been doing this for 30+ years and worked on quite a few Fast Strikes and has never run into this problem before. 140-143 compression on all 4 cylinders

[Bassmeister]

Float sticking or improper float drop on #4 carb is the only thing I can think of......

[ChampioNman]

Try this, use a portable tank, and get a buddy to ride with you. Mix the fuel at 50:1 in the tank you only need a few gallons of fuel. Cap off the pulse limiter fitting and plug the vacuum input to the VRO. Have your buddy pump the primer bulb while you run and see how it runs. I'm thinking the Air motor diaphragm in the VRO pump has a hole in it and the pulse limiter is sucking fuel into #4 cylinder. By capping off the pulse limiter and the vacuum inlet on the VRO this will eliminate any possibility of fuel getting drawn into #4.

[bjsmith919]

Thanks for the responses so far. Last night he pinched the hose that goes to the pulse limiter closed with a pair of needle nosed pliers and held it a while but it didn't have any effect on the engine. But that was while sitting in the shop yard and not under load. Will pass this info along to him in the morning and hopefully he'll go out with me to give it a try.

[omcforever]

How long did it run with the pulse limiter plier'd off with the needle nose before it ran out of fuel?

[316jughead]

Ignition test on the water? Did he run the motor at the rpm's that the problem occurred and tested each cylinder for spark or voltage at the primary coil connection? If a running output test, including a indexing test shows good spark on all cylinders, or at least #4, at the rpm range that the problem occurs, then I would think carb. Is the center nozzle well gasket in place? High speed jet in place and tight? Intermediate orifice in place? Float level and drop correct and needle not sticking? Vent not plugged up, check all passages as described in the service manual. Check all of the hose routings. Does your tech have a dyno or a test wheel?

[bjsmith919]

He had a timing light connected to each wire while I run it on the lake at wot. Said 2 and 4 were breaking down somewhat between 3 and 4500k as well. Put new power pack on it back at shop but haven't had it back on lake since. That was Thursday evening. Carbs were rebuilt by me, floats set level upside down and have a inch and three sixteenths drop when flipped, can also hear the needle click when opened. All jets and orifices cleaned and in place tight. With breather off, the same amount of fuel comes out of all 4 carb straws, I know that's not what they're called but don't remember the technical term. Run a spark check after new power pack was installed and have strong blue spark on all 4 wires. Not sure on the dyno or test wheel.

[bjsmith919]

How long did it run with the pulse limiter plier'd off with the needle nose before it ran out of fuel?

He didn't let it shut off. Held it closed for about 30 seconds and there was no change in the motor

[bjsmith919]

It is definitely getting too much fuel instead of not enough. We removed the dead man's cord and turned it over with the #4 plug out and it shot mixed fuel out of the plug hole

[316jughead]

Carb float level set with the bowl gasket off, it should be. Float drop is incorrect 11/16 to 1 & 1/8 is correct. Most of us set the float drop at 1 inch.

[bjsmith919]

Thanks, will reset all the float drops. Would that cause the problem I am having though? Too much fuel and gravity is just taking it to the bottom most cylinder?

[316jughead]

The only time your float drop would cause a problem is with an empty or near empty carb. The needle will get cocked in the seat and may stick open. Did you set the floats level with the gasket surface with the gasket off?

[bjsmith919]

Yes, they're set level when the gaskets are off.