Thread subject: Whaler Central - Boston Whaler Boat Information and Photos :: 1989 Yamaha 90 hp, intermitten power loss

Posted by bigmike0601 on 07/18/09 - 1:48 PM
#1

I'll get up to high speed then the power takes a step down and stays that way. Sometimes the power is there while getting back up and sometimes not. Almost like it's going from 3 to 2 cylinders. Haven't started trouble shooting yet. Any ideas where to start?

Posted by Phil T on 07/18/09 - 4:23 PM
#2

Check the boot on the spark plugs wires. One could be old and not staying snug. Not a bad idea to change them out after 20 years of use.

Pull the plugs and inspect them each carefully.

Posted by bigmike0601 on 07/20/09 - 7:09 AM
#3

I just snugged up on the boots and havent didnt have an issue most of the weekend. I'll check the plugs and replace then move to new boots if still a problem. Thanks!

Posted by Bake on 07/20/09 - 8:41 AM
#4

I had a friend that got a pin hole leak in the water jacket cover plate there on the back of his 70 yamaha. The water was getting on the plug and wire causing some issues. I doubt you have the same problem just thought I would toss it out for something else to look at.

Posted by Frank Jones on 07/26/09 - 1:08 PM
#5

Years ago, I had a similar problem - turned out to be a pin hole in the fuel line so that it was sucking a little air.