1977 Johnson 85HP

[srl123]

I have a 1977 Johnson 85hp. Compression 110 on all cyls. New battery, fully charged with 1000 cca. With the spark plugs out, good spark as indicated by spark tester. With plugs in, no spark on any cyls.No significant drop in cranking rpms either way. I was told by a mechanic, most probably the stator since the starter wasn't getting hot. Any ideas?

 

[tashasdaddy]

Re: 1977 Johnson 85HP

i have no idea, what the stator would have to do with the starter getting hot. if you keep cranking, the starter will get hot, whether the stator is good or not.

unplug the big RED harness plug, then pump the solenoid, incoming pos lead to small post with yellow red wire. check you spark with plugs in, with tester. boots could be cracked and spark jumping to block.

 

[srl123]

Re: 1977 Johnson 85HP

No connection, he was just thinking that the starter might be getting hot and dragging-aparently it didn't appear to be. Also, I just replaced the battery cables thinking that there might be corrosion. No improvement.

 

[emdsapmgr]

Re: 1977 Johnson 85HP

First, I'd try Tas's suggestion-unplug the red plug and try to jump start the engine. This test is to eliminate any problems with the key switch/main wire harness. You can also test for spark when the plugs are in with an inductive timing light.

 

[ezeke]

Re: 1977 Johnson 85HP

You say that you have good spark with the plugs out. Is that a 7/16" sharp snappy blue spark?

 

[srl123]

Re: 1977 Johnson 85HP

tried unplugging the main plug and jump starting-no change. the spark was solid bright blue 7/16 as per spark tester. also tried disconnecting to kill switch wire-no change. it's the weirdest thing i've ever seen. usually you have spark or you don'have spark. that's why i replaced the baattery and cables thinking there might be corrosion. thanks to all-any suggestions are helpful-don't want to just start replacing things.

 

[Faztbullet]

Re: 1977 Johnson 85HP

Verifiy with a tach the engine rpm as if its not spinning 250+rpm it will not fire. Usually when I see this problem its a stator or starter. The starter can still have problems and not get hot. If it has the Prestolite starter toss it and get the Bosch as its a better starter. If it already a Bosch check the brushes as a worn ground brush will allow starter to operate but not a specified rpm, and you can test the amp draw to see if in spec's.

 

[ezeke]

Re: 1977 Johnson 85HP

Even with the best starter, you need all of the juice you can get out of the battery to make the starter do the job. Make sure that you a fully charged battery, like-new cables, and immaculate connections.

Any resistance is too much, and those old cables break down inside the sheathing where you cannot see it - especially at points where they bend a lot.

 

[srl123]

Re: 1977 Johnson 85HP

Thanks for the info. I'll check the starter today. Hopefully that's my problem.

 

[srl123]

Re: 1977 Johnson 85HP

thanks for all the input. I checked everything out and figured out what it was.
I took the starter off, cleaned it good even though it looked clean to begin with, reinstalled and it fired right up-go with the simple first.
Everyone on here is great and I really appreciate the info.
Thanks again.
Steve