200 Johnson won't go fast!

[Capn Mike]

2 years ago, when I bought my boat, I would get 5400 rpms at WOT, and the motor ran well (it's a 2000 OMC model.) But last year I started using Exxon TCW3 oil (sigh... it was cheap @ West Marine!), but after a few tanks, my motor wouldn't go more than 3000 rpms. Used the engine cleaner recommended by the dealer, put in new plugs, went to Mercury oil,but had only slight improvement. When winter came, I switched to a lower pitched prop (15 x 13) because of the extra canvas and gear, and was able to get 4800, but slower speeds, of course. Also switched to NKG plugs.<br />Now it's summer; took off the canvas and half the fishing gear and put the 15.5 X 15 prop back on. I'm back to 3000 rpms, and will take it back to the dealer for repairs. <br />Naturally I'm a little (OK, a lot!) apprehensive about what he'll find. Any ideas? <br /><br />(I think I might begin to hate the slogan in my signature....)|<br /> |<br /> |<br /> \/

 

[almost retired again]

Re: 200 Johnson won't go fast!

Hi Mike,<br />If I were you I would go back to the factory type plugs that it came with. Take a compression reading on all cylinders they shouldn't vary more than 15#., next make sure that you have spark on all cylinders. That 200 should push a lot more prop than that. By the way I use champion plugs in any Johnson/Evinrude that I work on.

 

[JB]

Re: 200 Johnson won't go fast!

Howdy, Capt. Mike<br /><br />I agree with ARA. <br /><br />You are probably running on less than 6 cylinders, and it has nothing to do with your oil or plugs.<br /><br />If you want to work on it, get a manual then come back to this thread and we can guide you through identifyling what is wrong.<br /><br />Good luck.

 

[Dhadley]

Re: 200 Johnson won't go fast!

Tripple ditto! The KGB plugs have to go! Take compression (as mentioned) and we'll go from there.<br /><br />Good luck!

 

[Capn Mike]

Re: 200 Johnson won't go fast!

Thanks guys; boy, you leave this site for a weekend, and the subject disappears to page 4! I'll look for a manual locally, but in the meantime have already purchased the Champion plugs. <br />While I'm changing them, would it hurt to try to induce a spark to the block? I'm reluctant to use some of my old hot-rod tricks on these modern type engines!