1978 Johnson 55 hp wont idle

[Mytts]

ok guys i have read literally hundreds of forums so thanks to those who help others this is a great way to learn.

ok I have had many problems since I bought this engine but after everythign i have done i cant get it to idle, it fires with the warm up lever and the choke on. sometimes it wont fire with the choke and i see alittle gas coming out of the air intake. also as soon as i drop the warm up lever it stalls out. my carbs are clean i suspect, i have taken them off but not disassembled so they dint take a bath. . I did blow out and actually removed the orifices the low and high on both carbs. compression is good on the cylinders 120/130,

the first time a ran this boat it ran nice as i recall until the linkage with the timing under the flywheel broke and i sat in the middle of the lake all afternoon and couldnt get it started. it took me 3 days to figure it out. now i have a seloc manual and have redone the lower leg, all seals and gaskets. still have not got it too idle since. when i touch the throttle there is a blurp sound and then the engien jsut revs up it seems late almost. if that makes sense..

So two things i can think of either the carbs are dirty in the places i can not see or could it be the reed valves? I doubt the reed valves but i need soem help this is gettign frustrating. I am learning lots and enjoying it but i feel like im missing something. im very mechanically inclined and gather i will need to keep cheching this post as you will ask many questions. Thanks guys hope to hear from you and i wont write long post like this ever again promise

 

[Mytts]

Re: 1978 Johnson 55 hp wont idle

i should also note that I did try adjusting the throttle linkage and the throttle roller to the cam. no change. maybe timing? anything?

 

[Daviet]

Re: 1978 Johnson 55 hp wont idle

What condition are the spark plugs in? Have you checked spark with a spark checker?
That motor has idle orifices, did you check them? May be time to overhaul carbs.

 

[Mytts]

Re: 1978 Johnson 55 hp wont idle

thanks for the reply, i did check the orfices and stripped them, then replaced them. unfortunately the availability for a 54d(the high speed orifice is low in my location) so ik replaced mine with two from a 70hp it might run atille lean is what i think. but still should not present me with the problems i am encountering. spark is good its strong i got shocked and it fires too so i know theres spark....both plugs come out with black on them it looking wet but it fires so im not thinking its a bad plug. and like i said the carbs were clean it could be that the low speed are plugged but i doubt that but i could be wrong. on that engine from what i can tell there is no real idle mixture screw its just the cam on the roller for the throotle so this has got me stumped.

 

[Daviet]

Re: 1978 Johnson 55 hp wont idle

54D is the high speed jet, the idle orfice is #9 on the parts breakdown.

 

[Mytts]

Re: 1978 Johnson 55 hp wont idle

yes sorry i meant that the 54D was the high speed orifice, either way, i dont think 9 is the number i have 31 on the upper and a 30 on the lower carb. i guess maybe your jsut looking at the number on the schematic

 

[Mytts]

Re: 1978 Johnson 55 hp wont idle

so today i took my carbs off and blew them out again, put them back on and went to the lake, same thing...it starts in the warm up lever and choke on. it fires start of, i drop the choke back and it takes off high rpm. and as soon as i drop the warm up lever it dies out and stalls. then if i try with the choke on gas leaks out the air intake. and i am pretty sure that gas is coming out of my hose that hooks up to back of the air housing and into the bottom of the intake. also as it is dieing if I try to open the throttle it doesnt help. anybody?

 

[Dhadley]

Re: 1978 Johnson 55 hp wont idle

It sounds like we still have a carb and / or a linkage issue.

When it does run, what rpm will it turn at wide open?

 

[Mytts]

Re: 1978 Johnson 55 hp wont idle

Thanks for replying....I have had it out twice both times I could get it to WOT it ran good at high speed but it did idle at that time. very roughly after running it at WOT. after dropping the warm up lever it stalls but i a m pretty sure if I ram it into forward as it dieing and full throttle it it will open up it is hesitant tho and i can take off. I dont have an rpm gauge but as far as i know with this engine(I have a seloc manual) which is junk! if i set the the cam follower directly on the idle slot ont eh cam that should get me close. But i have fixed jets on my carbs and the only adjustment i know is on the cam and follower to the carb. there is no idle adjustment or anything. i am very confused but not stupid. I have read reed valves but thats very rare...and i jsut checked and my butterfly vavles are closed on idle. but remember i do have a surge to when i flick the throttle with the warm up lever still up or half way is hesitates to rev . what am i missing? what are the chqances that both times the carbs were off and even after i removed all jets and blew it out that theres still **** in there?

 

[Mytts]

Re: 1978 Johnson 55 hp wont idle

Update ok today i pulled the plugs i know i have spark obviously since it fires but black muddy looking on the tips, kind of sutty it seems. not fully burnt..

 

[Dhadley]

Re: 1978 Johnson 55 hp wont idle

OK, first we have to know / make sure it's running on both cylinders. If the top end is way slow (rpm or speed) then it may be running on only 1 cylinder and will never idle correctly.

If either one or both plugs are sooty then there is an air leak somewhere. Make sure both carb butterflies are completely closed at idle.

 

[Mytts]

Re: 1978 Johnson 55 hp wont idle

well i went out to check but i am by myself so i tried until i pulled the bottom bbot off and the coil from inside the boot stuck to the spark plug. that sucks....

 

[Mytts]

Re: 1978 Johnson 55 hp wont idle

but i did feel spark, from both boots...but i know that doesnt mean the plug.

 

[Mytts]

Re: 1978 Johnson 55 hp wont idle

so that boot is permanent to the coil, so how can i just fix that holder inside the boot that sinks onto the spoark plug for a good connection? anyone...im working with one thing at a time....

 

[speedoflite2]

Re: 1978 Johnson 55 hp wont idle

sounds kinda like me problem I am having with my 1972 johnson 50 hp. Wont idle right and seems as if only on 1 cylinder. I believe I may have a power pack issue or bad wire from the pack to the plug. Not sure how to test but I had a wire break and tried fixing but didnt work.

 

[Bob427]

Re: 1978 Johnson 55 hp wont idle

ya me to i have a 3 cylinder and i get the same thing i do think it is igintion related just have not found what yet


Bob

 

[Mytts]

Re: 1978 Johnson 55 hp wont idle

ok UPDATE!

Well mr DHADLEY after fixing the boat this morning I found that my top carb sparkplug was not firing it had spark but stayed cool. compared to the bottom. So i replaced both it seems to sound better for sure. But then again i have dreamt boats so not sure how accurate it is. however this is good, i can now fire it up on warm up lever, then slowly drop it down but jsut before it hits bottom it stalls out. so as i close the butterfly valves the low speed idling jets should take over. i can hear it start to cough as it comes down then she jsut dead stops almost if you know what i mean. so i will go through this piece of crap seloc manual again but any other ideas? since i am closer this is good but just not there yet. oh and I also put fuel system cleaner in the tank too i thought it would be good for carbon build up and stuff, I was at CT this morning and couldnt find SEAFOAM that stuff is awesome. anyways any help guys would be much appreciated.

OH i should mention that when i fire it with the choke, it will sputters then i see gas coming from the front of the carbs throught the air intake. then i flick the choke off and it fires instantly. maybe an air leak? DHADLEY hope to hear from you sir...and thanks for the help the first time

Dave

 

[Dhadley]

Re: 1978 Johnson 55 hp wont idle

When the motor coughs or spits back it's caused by an air leak. Finding out why it doesn't idle properly is a matter of going thru the steps in order. Check compression first then spark. If those check out by the proper methods then look at the carbs. Once you know they're clean and properly set then look at the sync & link. Everything has to be set right. Including having the correct spark plugs.

 

[Mytts]

Re: 1978 Johnson 55 hp wont idle

well i went to check after your message, and looked on the ground and there is green liuid coming from the peehole jsut under the water intake on the lower leg. i had muffs on when i was running it earlier, my seals must be messed on iether the shifter or the driveshaft. unreal! anyone have any other ideas i will pull the leg tonight and check. I cant believe this it seems everytime somethign breaks. I know this happens with older engines but really this engine is really frustrating me. I will get back you DHADLEY....please keep checking thanks alot by the way

 

[Mytts]

Re: 1978 Johnson 55 hp wont idle

Well after all this here is the problem with the idling issue. It was my carbs, I replaced them with carbs from a 77 Evinrude, and it idles fine now. so i guess the old ones will need a carb cleaning. Thanks for the responses, It was much help. The funny thing is i have read many forums and I was convinced it wasnt the carbs, it just goes to show that a person should never over look the obvious. There are many forums that talk about carb rebuilds first, and they are right!