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1977 85hp starting issue.

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brianc31525

New member
It's been prob. 6 months since i last crunk the motor and while it was running I noticed it was trying to drop a cylinder on me, you could just barely hear it. I crunk it again 2 weeks ago and had a hard time getting it running and she was missing on 2 cylinders. I have one coil that is cracked through the bakalite, but it was running fine on it, planning on replacing it. Should i replace all 4 as they are the same age? I need a new key switch for sure, it is hanging up. Could the key switch cause this kind of issue or am I looking at a power pack to? Trying to get a rough estimate of what I'm going to save up for.
 
You have 2 carbs on that motor, so if 2 cylinders are not firing, a clogged carb is a possibility. Considering the age of the motor, a power pack and a stator may be needed if they are original. I have a low hours 1975 85 hp and I had to replace both of those items a couple of years ago. I also replaced all 4 coils.
 
Using ethanol fuel? I hope not. It will destroy this motor. Pull all plugs and check for spark with a gap tester set to about 3/8 to 7/16". Crank with fully charged battery, be sure to remove fuel supply. Spark should jump nicely with a lightning like white/blue streak. Also I recommend doing a compression test and report back with results for each cylinder.
 
Marine gas only no doubt. Comp test shouldn't be neccessary. It's got more hrs running in the yard than in the water. When i got this motor it prob had less than 40hrs. on it and had never seen saltwater. Drove 6 hrs. inland to get it. Mint condition is all i can say. I do have a comp. tester and when i get the key switch replaced will do that but i don't expect any suprises there. Carbs are spotless already went through them. I always run all the fuel out anyway. I'm thinking power pack because it was running fine sitting in the yard except if you listened to it you know what it sounds like at idle and it was trying to drop a cylinder. You could just barely hear her stutter. Month or two later hard start and missing on 2. Got to be electronic that went bad. Thinking about putting CDI power pack and coils on her, are they any good? Have always run OEM before. Gonna order my key switch today and get that fixed then see if it makes a difference. I just hate opening up that remote box.......PITA. I do know thats a heavy beast. Was all 3 grown men could do to lift it off the transom and load in pickup truck.
 
Yes CDI Electronics is a good company. I've used lots of their product on my repair work over the years.
 
Am I going about this the right way and correct in my thinking Switch first that should take it out the equation, then test my coils with multimeter, and if they are good it's the power pack.
 
Switch is important. You must make sure no power can enter the black/yellow wire. That wire when grounded will stop the motor....no spark. Be careful never to allow power to get into the pack at this wire. Once you can safely spin over the motor, you should check spark as mentioned previously.
 
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