1978 Johnson 55 hp wont idle

[Mytts]

Re: 1978 Johnson 55 hp wont idle

ok now everythign is good to go except the idle still. I can get it to idle but its rough, and the idle adjustment screw above the throttle lever and under neath the timing linkage is all the way screwed in and and still my motor stalls eventually on idle , i have had it running for an hour but somethign not right, it bouces alot and my rpm jumps between 50-150 very fast and the motor jumps alittle. my advance timing is good 19 degree, base timing seems to be 4-6 degrees. Anyone any ideas, I cant check the power pack without the johnson tester so im stuck not sure what to think. the idle screw shouldnt be in that far im sure, and it should idle better, as soon as i put a load on it in forward it want to die out unless i ram the throttle to wide open.

my RPM fluctuates between 950 to 650 where it eventually dies out. usually 700 -800 is shere it sits but jumps high and low. like it want to die.

 

[Dhadley]

Re: 1978 Johnson 55 hp wont idle

Does it still sneeze just before it stalls?

 

[Mytts]

Re: 1978 Johnson 55 hp wont idle

i cant say it sneezes, there is no gas coming from the front of the carbs if your questioning reeds, it idles fo r as long as it can, and i can tell just when it is about to die. it fights through but eventually dies, but the rpm has to drop to 700 then it starts to die out, but even at that point my idle screw is still all the way out and if i push the throttle and advance a touch and idle at 1000 still boucing quite abit on rpm i can maintain it and it wont die, but its at the point where screw touches the stopper, where it starts to die but could run for awhile. and that screw is tight i cant get anymore out of it. what am i missing.

Mr Dhadley sir,

When its idling it seems like my firing is off, or one spark is missing. but i do have good spark now, and compression is 135, 140. I know its old but its driving me crazy, and i have alot of parts for it now. So i want it to run good. Thanks for the reply. I will go run it right now to double check the sneeze, I will fill you in.

 

[Dhadley]

Re: 1978 Johnson 55 hp wont idle

If it seems like it's not pulling fuel at an idle but doesn't sneeze then you could have stuck lower rings. Do a real good decarb, maybe two, and see if the base vacuume picks up.

 

[Mytts]

Re: 1978 Johnson 55 hp wont idle

ok Mr Dhadley, I did a decarb this afternoon, actually twice like you said. and I did not notice a difference at idle. my RPMS are stil jumping around. the block dies if i pull off a boot on either cylinder. the weird thing is the off balance, the bounce of the engine, when that happens thats when the rpms seem to fluctuate. my idle screw is still all the way in and to idle it has to be a touch farther to be steady. what else should i try? thanks for the help by the way.... I very much appreciate it.

 

[ronsealdeath]

Re: 1978 Johnson 55 hp wont idle

Hi there I have an Evinrude 55 with this exact problem, as described by you here. My motor jumps and splutters at idle with no advance on the idle adjustment screw on the cam connected to the bottom throttle linkage. I have done a decarb (lots of sludge came out), new plugs, checked compression (95psi cold, no throttle, both cylinders), replaced vacuum lines to fuel pump, rebuilt fuel pump and cleaned carbs with rebuild kits.
Still idles like a piece of c##p.
Have you had any success Mytts?
I reckon it sounds like fuel delivery from low speed jets for me. I say that because when I rebuilt the carbs, no matter how hard I tried I could not undo the low speed idle orrifice screws. The ones I mean are number 36, 37 and 38 on the diagram attached. Now my manual seems to think these should be unscrewed slightly to set idle correctly. Is this right? If so, how on earth do I undo them! Even so I reckon I need to get some carb cleaner in there. Aside from that it could be timing but that is beyond my very limited knowledge of 2 stroke engines.
Mytts, if you are like me you must be embarrased to take your mates on your boat. Every time it goes in forward gear in the water, it stalls out unless I get it right and put a load of throttle on it. In the driveway on the mufflers it doesn't stall, but I guess there is no load on the exhaust or prop. Any ideas?

 

[Mytts]

Re: 1978 Johnson 55 hp wont idle

Well first of all, the slow speed orifices which use the id numbers 30, and 31(found on the orifices when taken out) depending on your location are really hard to remove. and i bet if you couldnt get them out you stripped the heads like i did!. You have to use a wider than usual blade flat head, if you use the wrong size you will strip it for sure. you have to have the right size, and one could be tighter than the other depeding on who put it in the first place. you'll have to use an easy out. Every boat mechanic i have talked to said not to remove them because there a hassle to deal with and replace because no small shop carries them. you might find them depending on your location. i said 30, and 31 because depending on altitude these might be different, for example mine is 31 top and bottom 30(i believe). They have to be snug in the thread so i dont belive loosening them slightly should change anything. shoudl run worse i would think, i remember doing that on the water and remembering it changed idle but i couldnt maintain it. So dont try.

This weekend i had mine out in the water, with the idle adjustment screw all the way in and not touching the stop, it is held in by the fine tuning of the throttle cable, i can idle around 1000 it jumps allitle but will idle and shift nice. it only stalled twice when going from neutral to forward. started everytime, and i never had to take the cover off the whole time, one thing i did change was the angle of the motor, i always had it on the top whole for the angle, i adjusted that to the second last whole fromt he bottom. I did this because i realized when choked it leaked fuel from the front of carbs, this helped that problem. ( i think i never took the cover off)

 

[ronsealdeath]

Re: 1978 Johnson 55 hp wont idle

Thanks, I will steer clear of those orifices then. Like you said, they are pretty chewed up from my efforts to undo the screw !
I don't know what to say on the rough idling and stalling I'm having. I reckon I may tune the idle on the muffs up by about 400 rpm and then see how it runs in the water. I am guessing from other posts that on the muffs she is a few hundred rpm out for when she is on the water.
My carbs need linking back up and synching, not sure I can do a good job from looking at my manual so may bite the bullet and take it to a marine mechanic to sort out.
Is timing something you have looked at? Seems easy to adjust etc... but could potentially make a big difference?
Will let you know how I go
cheers
Al

 

[Mytts]

Re: 1978 Johnson 55 hp wont idle

The only thing they look at is full Wot timing which is 19 degrees. the idle should be at 4 i think not really sure tho...i have not found any documentation about that at all. It could be your low idle orifice...take some small fishing line and run it through the front of the carb, thicker line will maybe push somethign through, and maybe some carb cleaner spray...also a paper clip will fit in the holes at the top of the barrel there is 3, maybe they are plugged, it maybe on fit in two of the three. give that a try...other wise let me know what the mechanic sais.

 

[Mytts]

Re: 1978 Johnson 55 hp wont idle

Also i jsut noted that your numbers from the diagram are showing then intermediate orifice which mine does not have, and i thought yours would not as well. but its the same thing....your low idle is the top one...

 

[ronsealdeath]

Re: 1978 Johnson 55 hp wont idle

Cheers Mytts. I need to take the carbs apart again I think. When I cleaned them before I just sprayed carb cleaner in to all the little holes. Where exactly do I need to get in to with the wire and so on? I have to admit I'm not 100% what is a 'jet' and what is something else! Bit of a newbie to the internals of carbs you see. So I need to take it back apart, open those orifices as well? and push wire in to all the holes I can find? Is this correct? Sorry if this is an obvious question, I didn't even attempt to take any jets or whatever out before as I heard you need a special tool and you can break things easily. So I left well alone. I suspect that carbs are gummed up somewhere.
How did you link the throttles all back up after? It looks a bit complex from my manual?
Cheers
Al

The only thing they look at is full Wot timing which is 19 degrees. the idle should be at 4 i think not really sure tho...i have not found any documentation about that at all. It could be your low idle orifice...take some small fishing line and run it through the front of the carb, thicker line will maybe push somethign through, and maybe some carb cleaner spray...also a paper clip will fit in the holes at the top of the barrel there is 3, maybe they are plugged, it maybe on fit in two of the three. give that a try...other wise let me know what the mechanic sais.

 

[Mytts]

Re: 1978 Johnson 55 hp wont idle

The book makes it sound alot more complicated than it actually is. read the sections first and you will understand what i mean. THey go through alot of different years in that book if its the same one. But with carbs for example ours is fixed on both high and low, no needle valves and it sounds like you might have and intermediate orifice. so at the top of the carb there is a screw that is removable, and then some packing will be with it or left in, you will see it, then that hole follows the channels you see molded on the outside of the carb, then you see those silver caps about dime sized or smaller? there are removable and they open up more of those channels within the carb.Remmeber tho you will need a carb kit if you remove those. I also encountered a problem too with carbs you have to have a gasket on the intake and carb surfaces, there can be no leaks at all. they also come in carb kits. remember dont remove the orifices just the screw plugs before it. you'll see just look at your diagram again.

the hook up for calbes is easy too, and the link and sync issounds way more complicated then it is. these motors are actually really simple, you just have to get the basic components down. trust me..jsut read them again and you will agree..

 

[ronsealdeath]

Re: 1978 Johnson 55 hp wont idle

Cool, cheers. Will try and get those screws out and clean inside. I rebuilt the carbs with a kit this week but couldn't get at anything properly cos I couldn't get those screws off. Will poke some thin wire here and there as well to clear them out properly. I have to say they looked very clean nside when I went into them but that doesn't mean something isn't lodged in a jet I guess?
Will check out the link and sync again, I just need to get stuck in once the rain stops.
I have only one gasket on carb to inlet manifold but it is a new one from my carb kit? Shouldnt be any leaks but I will bear that in mind.
Cheers for the advice, good luck!
Al

 

[Mytts]

Re: 1978 Johnson 55 hp wont idle

Just wondering did you figure it out?

 

[ronsealdeath]

Re: 1978 Johnson 55 hp wont idle

Hi Mytts,

Well I put it all back together and it runs exactly the same on the muffs as before. I'm taking her out off the beach tomorrow to give her a run to see how she goes. I have tried turning the idle up a few 100 RPM as I read that it can run several 100 RPM lower on the muffs. I don't have a tacho (that works anyway) to give me a reading but did all the link and synch from the manual (you were right it was simple) and tried to just play it by ear on idle speed. It must be 1200RPM ish on the muffs. I am going to see if she bogs when put in gear tomorrow. I don't want to wreck the bottom end but may try turning idle up a tiny bit if she is still rough at idle in gear.
Going to test the spark gap tomorrow as well with a home made tester. Have no idea if that could be related to the rough idle but worth a check just out of interest.
So essentially I have definitely got good fuel system, good compression and as yet unknown spark condition. So I guess it could be spark related?
I'm probably being a perfectionist but most of the motors i see running on youtube are a lot smoother than mine at idle? and stalling out at sea when put into gear is not ideal !
Will let you know if we make it back to shore!!! Have to get it running better as we have just bought some waterskis. Bit worried about it all coming together to be honest.
Any luck yourself?

 

[Mytts]

Re: 1978 Johnson 55 hp wont idle

Your right about the idle, like i said mine idles around 100 in the water and I had to do that in order for it not to stall out. it shifts fine and apparently one boat mechanic i talked to always puts them at 1000 in the water. So you will be fine. mine stalls out 1 out of ten times advancing from N to Forward. But your engine starts up perfectly you will be fine, I also found that id I pushed the throttle faster it might not stall sounds stupid but it worked. Your right the other motors are smoother running thats what i thought too. I cant get mine to do that at idle, if you can run at high speed smoothly then spark plugs might not be the answer however they do talk about gap beign better for trolling or speed so maybe however i just use the recommended champion spark plugs J somethings. Your close let me know what happens... one last thing since this is a test run for you let it warm up first, and also spray your starter with grease so you dont beat teh crap out of it, I made that mistake once too.....luckily i have two...one parts engine.

 

[ronsealdeath]

Re: 1978 Johnson 55 hp wont idle

It all went a bit pete tong (wrong) today. We put her in the water and she fired up really easily, warmed her up for 5 to 10 mins and let her down to idle where she was actually not jumping around too much and not stalling out or anything. Put her in gear and she didnt stall and we set off along the coast. She was stuttering a bit though, kind of missing and not getting up to full RPM on WOT. So I carried on for 5 mins at pretty much WOT and turned back to the slip. Backed off the throttle a bit to about 3000 RPM and she just died straight away.

Tried to start her and she would not fire. Gave it loads of choke and it fired after a bit but only kept running for about 10 seconds before crapping out even with the warm up lever on half way up. We tried for ages to start her but we could only get her to fire with loads of choke and then it would only run for 10 seconds. Oars out! Got back to the beach and took her home in disgrace.

Back home I got her to fire again with loads of choke and managed to keep her going by using the throttle linkage to rev her up to about 3500 RPM plus but below this she was wanting to stall out big time. Took the plugs out and they were dry. Now I know we are getting ok compression and spark is there on both cylinders. I guess it is fuel starvation or lean running etc... Gonna take apart the fuel pump again and see if that helps. Besides that its going to the mechanic or we just move her on for something else which would be a shame. Getting a spare engine would be a shout though, may look in to that.

Its getting towards Autumn now so not going in the water again. Bit down to be honest but we will see what we can do for next year maybe?
Cheers
Alex

 

[thewilliampage]

Re: 1978 Johnson 55 hp wont idle

I am not 100 percent positive about the 1978 but my year model has a channel on the intake manifold at the reed boxes. If it has blown a hole in that gasket it will not let the idle mixture be right and spit gas at low speeds. It will totally mess with the air mixture. Then you try to adjust all the timing and linkage to wrong air mixture. Pull your carbs. Pull the manifold. Check the seal on the reeds. You can dissassemble them and clean them but do not force them to close. If the reeds are sooty or the reed box is sooty, dissassemble and clean them. You do this by finding a very flat surface and use a mixture of water and baking soda and rub them flatly in a circular motion. DO NOT use anything more abrasive. the baking soda will remove the build up but not the metal. Be sure to clean well with water. Put it all back toegether with a new intake gasket. Once its all together you might have to readjust your timing linkage again now that the air mixture will be right. That should solve your problem. The gasket is around 10 bucks. good luck