High RPM on start up after sitting.

MarkWalker

Site Supporter
Location
Buffalo NY
Anytime my ski sits for a few days, when I go to start it, the RPM's go way up for about 20 seconds (feels like forever) and then slowly comes back down to idle. Any idea how I can stop this from happening? Thanks!
964 TPE
Dasa 48's
RRP pipe
Zeel
 

Jcary85

Site Supporter
Location
Glenmoore pa
check for air leaks. Sounds pretty normal though. Are you priming it somehow? If not, prime it and see if it still does it (choke the carbs somehow - hand over each carb for a couple seconds, flame arrestors covers, etc)
 
Might seem dumb but I had an old throttle cable cause this, it would tighten up a bit sitting a couple days and hold the throttle open a bit with the pole down so I would have a high idle when I first fired it, after picking the pole up and working the throttle a bit it would return fully.
the other thing I’m wondering is if it could be idled high but rich enough that it idles slow when warm, but on the initial start when it’s lean from being cold it idles high till it warms up a bit
 

waxhead

wannabe backflipper
Location
gold coast
Relax. most skis with zeels do this. I really don't know the reason why. I can make an educated guess but they all do it for a for about 5-10 seconds. I think it has to do with the advanced timing and the lean mixture from fuel not being atomized on the cold engine. it probably goes to about 3000 rpm and then settles
 

MarkWalker

Site Supporter
Location
Buffalo NY
Relax. most skis with zeels do this. I really don't know the reason why. I can make an educated guess but they all do it for a for about 5-10 seconds. I think it has to do with the advanced timing and the lean mixture from fuel not being atomized on the cold engine. it probably goes to about 3000 rpm and then settles
It probably is 10 seconds. But it feels way longer!
 
As Wax has said it's a lean fuel charge from sitting and drying out. MSD enhancers sometimes do it too when you install them for the first time when swapping out the stock CDI for one. Since you're having it happen more often, next time you ready to shut the ski off after a ride and evacutating the water from the waterbox, rev it up with a quick flick of the throttle, hold the kill switch and hold the throttle wide open at the same time. This will bring a rich fuel charge into the engine and also act like a shot of primer for the next time you fire it up. That should also help with the lean runaway condition. Some carbs just bring in too much air for the size of the cases which dries them out more, just need to offset it with a good throttle dumping on the wind down.
 
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