Started the FX-1 today, noticed problem!

[dirkdiggler]

I did a search on high rpm/revs high etc......couldnt find anything!


I started the FX-1 today and noticed a problem! It will start and run fine but when I give it a little gas it will somethimes rev super super super high with only a little press of the throttle. I get scared and always hit the stop button so the motor doesnt blow. Like I said, it does not do it every time but only sometimes. What should I check??

Also got the turf on the rails, what ya guys think??

 

[Mike W]

Is your throttle sticking open?

 

[Mouthfulloflake]

it looks like crap and its about to blow up.

im kidding.

might be an air leak, you need to pressure check the engine to find it.

Or, simply make sure the carb and intake gaskets are all good, and check the carb for tight, and hope for the best.

 

[wydopen]

didnt you just crapily fix one of your gaskets on the intake???..if so its probally leaking air..its much easier to do stuff right the first time instead of doing it twice

 

[ger87410]

Isn't that a 2-cycle engine? Can you over rev it?

I don't think you can my 2, or a 2-cycle chainsaw engine. What happened to the rev limiter? Is it removed and that's why you're afraid to over rev the engine?

The condition you described sounds *almost* similar to what I experience first start of the day until the gas gets pumping good into the carb. It revs a little higher then normal, but always drops back down after a few seconds.

 

[wydopen]

Isn't that a 2-cycle engine? Can you over rev it?

I don't think you can my 2, or a 2-cycle chainsaw engine. What happened to the rev limiter? Is it removed and that's why you're afraid to over rev the engine?

The condition you described sounds *almost* similar to what I experience first start of the day until the gas gets pumping good into the carb. It revs a little higher then normal, but always drops back down after a few seconds.

no with an air leak it can run away and "diesel" where even if you cut spark the motor will keep running till out of air/fuel cause the plugs get so hot...its quite scary and w/o any water running through your in big trouble...the way to kill it is to hold the throttle wide open and hit the stop button...but you still need to figure out why its doing it

 

[thegoldenboy]

Air leak for sure. Check carb base gasket first. I had a beauty airleak once on my 650. As soon as you hit the green button the motor would scream to the heavens. Scared the crap out of me as it was the first startup of the year.

 

[special fx]

Hmm....I buy air leak, except you state hitting the stop button shuts it down. With air leak (lean runaway) the stop doesn't do crap.

 

[SuperJETT]

Whenever you have a runaway engine, hold the stop button and OPEN THE THROTTLE WIDE OPEN. An airleak is bypassing the throttle plate, so you need to open it to remove the bypass.

 

[Mouthfulloflake]

not exactly.

take a chainsaw, turn the highspeed screw in about 1 turn.

hold it wide open, it will likely come apart.

better yet, take the chain off of it, hold the throttle down, wear a face shield.

my point is YES you can easily over rev a 2 stroke.

the only reason you dont over rev skis is because of the rev limiter, and the pump stays loaded in the water, that keeps the engine rpms low enough generally.

Isn't that a 2-cycle engine? Can you over rev it?

I don't think you can my 2, or a 2-cycle chainsaw engine. What happened to the rev limiter? Is it removed and that's why you're afraid to over rev the engine?

The condition you described sounds *almost* similar to what I experience first start of the day until the gas gets pumping good into the carb. It revs a little higher then normal, but always drops back down after a few seconds.

 

[snowxr]

Ya gotta jiggle the handle. Then everything will be fine.

 

[D-Roc]

dirk is this the 701 motor that you rigged the leaky base gasket on? if so the REPLACE THE BASE GASKET. which sucks because we will have 1264 more questions to answer. check to make sure that your fuel lines are primed. if they have air in them it may cause the carb to go lean and rev high. if your working on setting up a carb on a motor and the pop off is too high it can also cause it to rev up. it may idle fine but if you give it a tiny bit of throttle away it goes.

 

[McDog]

The ski is looking good, though. Too bad it isn't running as good as it looks.

 

[Captain PegLeg]

How do you do a pressure test on a ski? I gotta find my exhaust leak on my 650...

 

[ger87410]

I forget how. I researched it a few months back.

Look for 'leak-down test' :fing02:

 

[jet pirate]

my superjet would run on occasion and checked for airleaks and none. turned out my rear cylinder was scored pretty bad and allowed air past rings .check your compression ! the crazy part was mine was only off 7 pounds !! and the piston skirt was hashed !!

 

[jet pirate]

an easy way to psi test is bolt a plate over your intake and exhaust and take a rubber valve stem from a car wheel and buff the rubber off stick that in a hose and hook the hose to your pulser pump up with a bike pump should hold 7-10 psi for over an hour