120 Johnson - No fuel to cylinder and carbs spitting fuel - please advise on possible

Finally took this 120 out to the water and did some more testing and could really use some advise on what to check next.

After I cleaned some bad connections it seemed to idle and start much better on muffs but was not the case when it was in the water. It was hard to start and would barely stay running again now that it was submerged.

I did a couple tests that I found on this forum and now need to figure out possibly causes based on my findings.

Carb Check with cleaner:
Sprayed the cleaner in each cylinder and three of them would cause the motor to choke out when sprayed but one carb would REV the motor and make it sound better (well to my newbie ears).

Coil Check:
Pulled the plug wires one at a time and three of them would cause motor to run even poorer when pulled but one would not change a thing. Went ahead and swapped coils but had no change. Held plug wire and saw blue spark jumping to plug so "think" I can eliminate coil issues now.

ALSO..Spitting Fuel:
When I first took the carb cover off there was a bunch of fuel / oil in there and when this thing is running there is fuel spitting out of the carbs. Being a newbie still I am unsure if some fuel spitting is normal or not but this seemed excessive and it looked like it was coming from some gold colored screws (just read these are the idle air bleed orifice and the intermediate orifices).

update: previous owner had been trying to fix the rough running issue and had carbs professionally rebuilt, new VRO, fuel system cleaned out etc. but did NOT clean the totally corroded grounds all over the place (including seriously bad coil grounds).
possible theory from this newbie...grounds were causing original problems, he had all the above work done but didn't get it fixed..motor sat until he sold it and one of the carbs got gummed up. AND / OR this thing has a failing power pack or more bad wires somewhere.
Oh and the throttle advance was gummed up and not advancing when I got it..can't get the flywheel off to look under it though.

All help is greatly appreciated...thank you.

p.s. I can add photos and or video if that helps.

Re: 120 Johnson - No fuel to cylinder and carbs spitting fuel - please advise on poss

Reading other threads has made me wonder if the timer base can cause intermittent issues like what the previous owner and I have experienced? or do they just go out? I tried and tried to get the flywheel nut off but had no luck (not that I would know what to do anyway once it was off..lol)

Re: 120 Johnson - No fuel to cylinder and carbs spitting fuel - please advise on poss

Check under your timing base some cases I've seen lube from the advancing rods made its way into areas it shouldn't and would break connections but not every time. But before I would go pulling the flywheel do a compression test on all cylinders and through us some numbers. Lets see if you have any problem cylinders. And when you pulled plugs and the engine got worse where the on the same side same head or scattered?

Re: 120 Johnson - No fuel to cylinder and carbs spitting fuel - please advise on poss

I have done a compression test and they were all at 125 and held firm.

The one plug that would not change the idle when pulled was the top left (standing in the boat) but the carb that would REV the motor when sprayed with carb cleaner was the top right (opposite side). Now I don't know even know if that carb actually goes to that cylinder or not..just figured it did since all three other plugs made it idle rough when pulled and the three other carbs choked out when sprayed.

The previous owner had and intermittent issue for almost two years..had carbs rebuilt, bought new VRO, cleaned all fuel lines but didn't tackle any electronics I guess.

I guess I need to figure out how to hold the flywheel in a way to let me put a six foot helper bar on my ratchet...just about popped my eyes out of my head last time I tried though...lol

Re: 120 Johnson - No fuel to cylinder and carbs spitting fuel - please advise on poss

Take your time when removing the flywheel. Soak it with penetrating oil. It's taken 48 hours in the past to free some of mine. In most cases set your puller crank down until its good and tight if it doesn't move at all walk away check it again in a few hours. I've had some move just a hair at a time until free and others that when I came back they came right off. But have patience. If you rush or start beating on it you will almost certainly damage your flywheel and i assure you there is not a warehouse full of them to just order a new one. Besides that flywheel has been perfectly balanced for your specific motor and changing anything could cause later problems. I've replaced a flywheel from one motor of the same year serial and hp to another and it just never felt right again. In theory it should have been fine. Me personally I wouldn't chance it and spend money that could be avoided.

Re: 120 Johnson - No fuel to cylinder and carbs spitting fuel - please advise on poss

71Windsor said:

Take your time when removing the flywheel. Soak it with penetrating oil. It's taken 48 hours in the past to free some of mine.

Click to expand...

I had actually been spraying this about 3 times a day for maybe 4-5 days before attempting anything.
I am using PB Blaster, have read that was the best, if there's something else I will gladly try.

71Windsor said:

In most cases set your puller crank down until its good and tight if it doesn't move at all walk away check it again in a few hours.

Click to expand...

Took me a second to figure out what you meant there...then I realized you are talking about the harmonic puller.
reason it took awhile is I haven't gotten that far yet...it's the NUT that I cannot budge. I tried by myself with a flywheel holder in one hand and the ratchet / socket and pipe extension in the other hand..said a few choice words and gave her all I got..nada..zippo..ziltch.
Tried again the next day with my wife holding the flywheel holder and all I did was pull her around...lol

These aren't backwards threaded are they..man I just thought of that...err..that would suck..lol

And I have read threads about beating the flywheel etc. so I will be careful there, thanks.

Re: 120 Johnson - No fuel to cylinder and carbs spitting fuel - please advise on poss

If that cylinder is not firing and the carb is spitting back fuel it sounds as if you have a reed problem with that cylinder.It happened to me with a 75 Stinger.When I took it apart I found a screw wedged under the reed.I can only think it was left there on a previous stripdown(not by me)'cos the screw was one of those that hold the cover on and could no way get inside.Anyway,if that turns out to be the case be very careful.A few weeks after I fixed it I was routinely running it at a fast idle (recomended with all outboards every few weeks during the off season) when it threw a rod and wrecked the casing.It had not occurredto me then that if the reed was not working ,no fuel was going to that cylinder,But NOR WAS ANY OIL either.Hence terminal damage.I hope that is not happening to you but just thought to warn you .
Geoff69a1

Re: 120 Johnson - No fuel to cylinder and carbs spitting fuel - please advise on poss

Thanks for the heads up Geoff...I will put some tranny fluid into that cylinder before I ever run it just in case.

I am working all week so haven't had any time to work on this yet but can someone tell me if the Flywheel Nut has normal threads or if it is reverse threads by chance? That's what I can't get off.

Thanks.

Re: 120 Johnson - No fuel to cylinder and carbs spitting fuel - please advise on poss

Just a thought but am currently having an issue with mine, my middle carb was spitting fuel...ended up one of those lines that goes to the bottom of each cylinder on the intake manifold (to the check valves I think) was broken...if youre going to have the carbs off again, it might be worth pulling the intake manifold to inspect the reeds and make sure none of the passageways which are part of that check system are clogged. Once I fixed the hose, no more spitting carbs (tho it still wont idle


All youre gonna need is a new intake manifold gasket (about $8)...

Re: 120 Johnson - No fuel to cylinder and carbs spitting fuel - please advise on poss

I finally got the nut off the Flywheel...had to wait until my parents neighbor had time to help me and his big impact wrench did the trick.
I will be trying to get the actual flywheel off tonight with a puller and then will be trying to troubleshoot this motor as soon as I can.

If anyone has any tests I can run, advice on what to try etc. I would be grateful since all I really know to look for right now is a sheared key and bad magnets.

On that note...can the trigger base being gummed up (sticky) cause a carb to not get fuel? I don;t really know what the trigger base does yet.

Thanks.