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1978 Johnson 85 hp misses on one cylinder when cold

R

RoyBrew

Member
I have a 1978 Johnson 85 hp that started missing on one cylinder last winter. Mostly happens when first started and cold. It may idle with all 4 cylinders hitting until you start to speed up. The miss starts and ends suddenly. Its like the cylinder cuts off quickly ant any time or speed and when it starts to fire again it just kicks in an runs like there was nothing wrong. Runs strong when warmed up. Help.
 
Do a cylinder drop test on it to see if you can find the cylinder/cylinders that are missing and go from there.
 
Thanks Boobie. Sorry I haven't replied earlier, been working a lot of hours. going to have to wait for cold weather. Just had it out and I think it might have hic-uped at the start for maybe a second, but ran like a champ after that. only does when weather is 50 or below. could it be a sticking reed valve? Oh well I let you know. Thanks again.
 
Reed valves are multi-petal and not likely the problem at all.------Does it also do this with cover off the motor ?
 
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