1978 85hp johnson seahorse 1 cylinder not firing.

[johnyjo]

I would appreciate any advice i can get. just cant afford to take it to the shop(yet). i have a 1979 85 horsepower Johnson. top right cylinder(from behind) wont fire. its got spark, the plug comes out coated with dark almost black oil/gas??.

i replaced power pack on this side
rebuilt carbs
new coils on right side.
compression test on this cylinder is 117ish.

the boat idles out fine mose of the time running on 3 cylinders i assume. but give it throttle and it usually will die.

any advice? what should i do next.

 

[crb478]

Re: 1978 85hp johnson seahorse 1 cylinder not firing.

how did you verify it has spark? Will it jump a 7/16 inch gap with a sharp blue snap? You can also try to swap coils and power packs from side to side one at a time to see if the spark issue follows the coil or power pack. Just because they are new does not mean they are good. Cleaning all of the grounds and connections may help also, sometimes it is something as simple as not having a good ground.

 

[tashasdaddy]

Re: 1978 85hp johnson seahorse 1 cylinder not firing.

it sure sounds like a carboration problem. when you cleaned the carbs did you do this. http://forums.iboats.com/showthread.php?t=244013
also did you do a link n sinc.

 

[johnyjo]

Re: 1978 85hp johnson seahorse 1 cylinder not firing.

its definitely sparking
i bought 2 used power packs and 2 seets of coils. swapped em all in and out.
removed spark plug boot and held it to the engine cover to verify spark was there...is this correct way of doing it?
i cleaned the carbs, soaked them, used wires to clean the jets...not sure if anything on the carbs could be out of adjustment?

maybe i could switch the top and bottom carb and see if the problem follows?

only other thing im thinking is it possible to have water in the cylinder? in small amounts would that cause it not to fire?(head gasket?)
im stumped

 

[johnyjo]

Re: 1978 85hp johnson seahorse 1 cylinder not firing.

oh yeah
i was also thinking if it had any amount of water in the cylinder wouldnt the compression be down?

 

[johnyjo]

Re: 1978 85hp johnson seahorse 1 cylinder not firing.

this engine has 2 power packs for 4 cyulinders
is it possible for 1 power pack to fire one cylinder well and not the other?
or would both cylinders be down?
right now its just the one
im pretty sure i have a good spark, by my analysis anyways.
compression good, and plugs covered with what looks like wet oily dark gas mixture.....or is it somethign else?

 

[MikDee]

Re: 1978 85hp johnson seahorse 1 cylinder not firing.

Maybe your reeds in that cylinder are leaking, or bad? take a look.

 

[cdoliver]

Re: 1978 85hp johnson seahorse 1 cylinder not firing.

Spray some premix fuel in the throat of that carb while it's running and see if it picks up. If it doesn't your spark needs attention. if it does, that carb needs to be regone through. It could be a reed problem, does it spit fuel out the front of the carb while running?

 

[johnyjo]

Re: 1978 85hp johnson seahorse 1 cylinder not firing.

no no fuel coming out the carb,
ill try spraying some fuel down the throat and see what that does.

how do i know if a reed is bad? never looked at one before

 

[johnyjo]

Re: 1978 85hp johnson seahorse 1 cylinder not firing.

i think it is fixed.
i sprayed fuel mix into that carb and it did indeed pickup. i had been spraying wd40 into it and had no difference maybe it just wasnt combusting i dont know.so i pulled the carb and recleaned it.

thanx for all your advice im new here but im sticking around now!