Still Stumped??

[Javelin 353]

I have a 1991 70 hp Johnson have been chasing an eratic spark situation, Several times lately when using the boat it will loose RPm to @ 2800 middle cylinder has NO SPARK. Replace coils, powerpack, plugs and wires. Out again today same thing while limpping back to the ramp it just took off again and ran fine. I know it lost spark because I pulled the wires while it was running and got jolted by top and bottom cylinders and the engine changed sounds with these two. Middle cylinder dead as a door nail. Some times this will occur during a restart also.<br />What else should I check??<br />Thank You<br /><br />Ps. It has done this with 3 different Power packs 2 OMC 1 aftermarket

 

[Javelin 353]

Re: Still Stumped??

anybody???

 

[ob15]

Re: Still Stumped??

Have you checked all electrical connecttions? possibly a bad connection somewhere.

 

[rickdb1boat]

Re: Still Stumped??

Does it do this when the motor is first run or does it take awhile to start acting up? Swap coils and see what happens, if you have not already. Wouldn't be the first time someone got a bad coil, even new....

 

[Javelin 353]

Re: Still Stumped??

Swaped coils today made no difference. some times it does when hot some time when cold?

 

[KYHunter2]

Re: Still Stumped??

Did you ever , clean , ( shiney ) all connections ???? ie: coil grounds , powerpack grounds, check all wiring for weak , damaged, etc. wires, loose connections etc. etc . etc.<br /> With what you've changed , its possible, all this was for nothing. Anytime theres a electrical/ spark problem . <br /> I start with the basics of all trouble shooting . The simple and often overlooked , items.<br /> I seal all coil grounds, for that matter, any exposed connections, with 3M liquid tape . <br /> Its not the black type , ( though it works too).<br /> Its a brown/clear , and once dried . Is a very good seal, against moisture/ corrosion. <br /> I like the brown 3m the best, because its not as obvious, and comes off easily, if need be.<br /> <br /> Good-Luck,<br /> KYhunter