'68 Chrysler Revs High and Stays High in Idle and in Gear!

[robrileyw]

Hi to all in this forum, I just took my 1968 Chrysler 55hp out on the water today....As soon as i started it, the gas seemed like it was stuck and revving really high!...so i shut it off, checked things over, started it again...the idle was normal...I go to shift it in gear and it runs fine then all of a sudden the rpms go up high stay high, I put it in neutral and still revving high...shut it off turned it back on still running high. There was three foot waves on the water as well, which I don't think this would have anything to do with how high my engine is revving.
I would like to add that before winter I rebuilt the carb and replaced the float...I set the float to the correct specs...have the air screw on top set to 1+1/8 turn out...also a new needle and seat...I am stumped as to what the problem could be...Someone said that it might be the linkage or synchronization is out of adjustment...i've been trying to mess with idle screw on the tower but no cigar....Would could cause the high revs and the revs staying high???
Any help at all would be very appreciated since my last resort would be to bring to a boat mechanic...I do have a manual for this old Chrysler as well....
Thanks
Rob

 

[wickware]

Re: '68 Chrysler Revs High and Stays High in Idle and in Gear!

Have you looked at the position of the throttle shaft, plate and linkage to see if it dictates the high revs vs an internal sticking throttle plate? One or two carbs on the 55 HP? I have a 1970 35 HP Chrysler that I?m told is basically the same 35 ? 55 HP if they both have one carb. I have never seen or had this problem (with my carb attached) but feel the linkage position should tell you something about what is happening.

Could a bad vacuum hose or leak on the engine cause this as it would on some autos?

 

[robrileyw]

Re: '68 Chrysler Revs High and Stays High in Idle and in Gear!

Have you looked at the position of the throttle shaft, plate and linkage to see if it dictates the high revs vs an internal sticking throttle plate? One or two carbs on the 55 HP? I have a 1970 35 HP Chrysler that I?m told is basically the same 35 ? 55 HP if they both have one carb. I have never seen or had this problem (with my carb attached) but feel the linkage position should tell you something about what is happening.

Could a bad vacuum hose or leak on the engine cause this as it would on some autos?

My 55hp looks exactly like that pic and one carb as well. I'm new to boating in general and wouldn't know how to "set" the position of the throttle shaft plate and linkage...If you or someone else could give me some insight on doing so, I would really appreciate it!

 

[wickware]

Re: '68 Chrysler Revs High and Stays High in Idle and in Gear!

My points:

1. Is the engine?s linkage saying it should be idling as the attachment is showing vs hung in a higher RPM?s position?
2. My question ?To All?, would a vacuum leak increase the RPM as on automotive engines? If so, where are the most likely sources of the leak? Such as, any loose fitting or cracked hoses and spraying WD40 on suspected gasket leaks while running.
3. "To All", other reasons that would cause the engine to Rev High w/o you causing it?

Thanks To All Replies!