'92 15hp rich off idle

[jauguston]

Hi again guys.

I have a real nice running 15hp that has one annoying trait. From a little way off idle to probably 1/2 throttle it four cycles pretty bad. I keep rolling throttle on and at a point it will clean up and run smooth as could be.

Is there any thing that effects that area that can be worked on??

I am quite impressed at how well it pushes my Crestliner 1448 Jon boat. 25 mph with just me. It turns 7100 rpm at that speed. 21 mph with me and DW.

Jim

 

[Vic.S]

Re: '92 15hp rich off idle

Sounds as though the idle mixture setting is a bit rich. Have you tried weakening it a bit?

See the article on the Engine FAQs board to get all the details. HERE

(you only have the one adjustment as the high speed mixture is fixed.)


7100rpm sounds a bit high. I would have expected the maximum to be best part of 1000rpm less. I think you should check the engine spec and the tachometer accuracy. If necessary fit a larger pitch prop.

 

[jauguston]

Re: '92 15hp rich off idle

The 15 power is rated at 7000 rpm.

I have been all over the place with the idle mix but I don't really think the idle circuit is in play as I am opening the throttle. I am hoping there is something that can be worked with to make it better.

Jim