1995 mach 1 lean running - Snowmobile Forum: Your #1 Snowmobile Forum

123upmichigan · 03-11-2006, 09:20 PM

helo all just recently decided to try my luck with skidoo's picked ap a 670 mach 1. but has 1 problem, it seems that ever since new pistons were put into this motor and possible before that the machine runs lean on the top. snow white. tried jetting up, had 500 mains in it and still would not catch it. thought maybe the fuel pump<single> did not deliver enough pressure so now has dual pumps on it. also the cdi box was replaced in it last year. anyone have any idea's?

**smallengineguy** · 03-11-2006, 09:33 PM

Cracked intake boots? How does it idle? Maybe crank seals?

123upmichigan · 03-11-2006, 09:41 PM

idles great, all day long no problem only lean on the top end after 1/2 throttle

**smallengineguy** · 03-11-2006, 10:17 PM

Is it lean to the point where you lose power? If so, there is a lack of fuel issue( fuelpumps not strong enough, or obstruction in line/tank).

letitsnow · 03-11-2006, 10:47 PM

you shouldn't have to have 500 mains in it, deffinetly a leak somewhere.

123upmichigan · 03-12-2006, 10:14 AM

ok i will look for a tank restriction on it. also someone tried to tell me that maybe a center seal was going in it. but i thought that it would cause it on the low end more than anything. also could a rotary valve casue this?and yes it gets a lack of power from the lean conditions plunge the primer and picks right up

**smallengineguy** · 03-12-2006, 01:31 PM

Tank obstruction or the like.