98 challenger 1800 startup and stay at 3500 rpm help?

[stang7tl]

when the motors are started up they go straight to 3500 rpm's and stay and nothing changes it. move the throttle still at same rpm's any help? we had this problem before but it has been so long i cant remember what we did t fix it I want to say the RAVE valve? but pleas help.
thanks

 

[Chester]

It won't rev past 3500 - 4000 in neutral. Put it in gear. If it does it in forward, there's a problem with your neutral safety switch.

Chester

 

[stang7tl]

no it will sorry for not saying that. It is a matter of when flushing it stays at 3500-3600 both motors. is these normal? I would think so. I could see idel at maybe 2000 .

 

[cjb]

I think the shop manual calls for 3k RPM's out of water. That’s what I have mine set at. Any lower and it will have a hard time starting or not start at all when i water.

At what RPMs are the engines turning when in the water?

 

[kustomkarl]

The engines will idle at about 300o to 3500rpm's out of the water on the hose...in the water is should be at 1500rpm's due to the load on the impellers. Check the throttle cables to be sure they are in sync. and miss adjusted.

Karl

 

[stang7tl]

ill try the water soon I need to get it from a shop I told them not to touch it yet they said the carbs need to be rebuild and want 1000

 

[kustomkarl]

Yeks...you could buy brand new ones for a couple hundred...A manual would help in the rebuild and rebuild parts too. We have both available and advise too if you get in a jam. If your mechanically inclined, you should do it yourself and save a bunch of money.

Karl

 

[stang7tl]

yea it not that big of a problem we own a body-shop and mechanical but it been sitting and my father just took it up their to see about what it could be. we don't think its the carbs. we already had one off and it was fine. but we just think that 3500 rpm is high for them to be running at while flushing,maybe it normal?

 

[stang7tl]

where would be the best place to get the rebuild kit for these incase I did rebuild them

 

[timmyboy76]

i'd wait...

you got them off before, i'd take them off again, pull them apart, carefully, so no gaskets rip, have few cans of carb cleaner, dont lose the n/s spring, and clean the sh** out of them, reassemble, beforet hat though, make sure all the brass fittings around/protruding in to carbs are clear, if need be, use lighter, heat'm up, then blast....

 

[Chester]

The engine should be set at 3000 RPM out of the water and 1500 in the water. Have you tried adjusting the throttle stop? Is the cable improperly adjusted and holding the throttle open?

Chester

 

[Gunsrunner]

Yep they do rev high out of the water! Have you tried another tacho to make sure it is 3500rpms. I have installed tiny tach's digital tacko on each motor and use them when tuning, I have adjusted my idle control screws to give me 3000rpm on land and 1500 in the water, also make sure the butterfly's are opening evenly. Don't use the low speed mixture screw to control idle! it is used to get it's highest rev achievable with a smooth running motor. Then adjust the idle screw.
If they are reving too high you will hear them hitting the rev limiter and cutting out for a fraction of a second, when out of the water.
mine also has a load metal sound at revs which goes away when i grease the PTO, i guess it's the drive shaft transfering the vibration down to the impellor , that makes the sound. When it's greased properly it's nice and quiet. "well for a 2 stroke"
PS: Just search for the carby kits you will find heaps mine are Mikuni bn40-38