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I have a 2004 660 rhino .Could someone tell me what jetting to run to keep it from being so cold blooded at start up.
 

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I have a 2004 660 rhino .Could someone tell me what jetting to run to keep it from being so cold blooded at start up.
Is it starting up right away and then taking a long time on the choke before it will maintain an idle, or is it taking a long time to fire up while cranking? If it is the latter, it is likely that the fuel has drained out of the system while sitting. If this is the case, talk with Craig at Rutting Rhino, as he has some innovations in his fuel delivery kits that help a lot with holding the fuel in the plumbing.
 

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If it starts but you have to use the choke for a while until it warms up you need a larger pilot jet.
 

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I think technically you would want to go to a smaller jet. More fuel generally makes the motor run cooler. If you lean it out the mixture burns hotter.

That said, How long does your motor take to warm up? Unless it's frozen nipple cold mine takes.. MAYBE a 30 second to a minute before I can drive it "safely". You can also drive with the choke on too.
 

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If it starts but you have to use the choke for a while until it warms up you need a larger pilot jet.
I think technically you would want to go to a smaller jet. More fuel generally makes the motor run cooler. If you lean it out the mixture burns hotter.
It's definitely true that leaner is hotter...

However.... that is not the reason the larger pilot jet is better...going excessively lean is the wrong thing to do regardless of the reason for doing it...the stock pilot jet is already too small from the factory with very few exceptions...

The vehicle has a smaller than ideal pilot jet from the factory even for a bone stock intake/exhaust...while the main jet is in the ball park for the factory intake/exhaust.... and at any given elevation/temperature combination may be spot-on but will generally be close enough to not be a problem...

An otherwise bone-stock rhino 660 will start easier and run better with more power from a stop with at least a 45 pilot jet and it is an even bigger improvement in colder weather and/or higher flow intake/exhaust...

It will need less choke because it won't be as lean...when it's both cold and lean the extra heat from lean mixture does very little... if any good but the leaner it is going to lean side of ideal... the worse it will run with and w/o choke at all temperatures but much, much worse when cold...

Getting the ideal idle a/f and total fuel curve including the "low speed circuit" will NOT however make it get to full operating temperature faster...and people get confused in the terminology also and think that the pilot jet ONLY affects low throttle settings...which is NOT true at all...

The only way I know of to make it get to operating temperature faster is to have a thermostat...the rhino doesn't have one...therefore cold coolant is constantly being pumped through the cold motor making it take much, much longer to reach full operating temperature... which is about 155f minimum for good operation...

I never had a Grizzly but I am under the impression the grizzly's did have thermostats in the 600s and 660s...I have been told you CAN run a t-stat in a Rhino...but never needed one here... :dunno:

Hard starts are almost always due to lack of fuel in the float bowl combined with too lean of an idle a/f...

Along the same lines one can increase the size of the "choke jet" aka "power jet" aka "starter jet" aka "fuel enrichment jet"...

Stock is a 55... in extreme cold I would use a t-stat if it was doable...and I would always run the ideal combination of idle a/f setting, pilot, main, and starter jets regardless of anything else... for a lot of people that would be a simple matter if installing a 45 pilot jet and doing nothing else...
 
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