Hi Guys
Has anybody done a groove on a older snowmbile, mine is a 73 rupp nitro with a 340 tohatsu engine.

PS Sorry I know some you guys don't want to hear the word snow but I can't help it where I come from.

Thanks Aaron

Hi Aaron,

I haven't seen anyone put a post up about a snow mobile engine, an 85HP outboard engine has been done.

But I don't think a little thing like that is going to stop you.

If it's an easy process of removing the throttle body, you could take it in baby steps, ie: experiment a little.

On my lawnmower I did a full groove (full arc of the throttle plate), on my generator the groove arc was from the 8 O'clock position to the 4 O'clock position. (I recall somewhere that Ron had recommended a partial groove for the generators and that was my interpretation... Works great. More than doubled the run time)

On the vehicles I did full groove. If the bore on the throttle body is small, I would probably go small bit with the partial groove and give it a try.

If you find a big change for the better you can stick with that or take it to the next level... full groove.

I think you will find it works either way but its always interesting to know if there is a difference.

Don't forget the spark plug gap, approximately 20% more gap.


Your burning daylight, let us know what you end up with.

Karl Fortner
Tacoma, Wa.
Gadgetman Tacoma

Hi Aaron,
I haven't modified a snowmobile but have certainly wanted to...just don't have one to do. Look forward to hear your results. It should be exciting. I did do a chainsaw with some amazing results. You can see it on the forum in this section. If you have any questions, don't hesitate to call me at 607.590.0391.