Engine runs, but won't rev past 4000. Please Help

[pincusa]

I finally finished replacing or rebuilding both engines in my '99 Challenger 1800. I've idled both engines to let them break in a little, and now it's time to run the boat. But both engines won't rev up. When I push the throttles past 1/3 or 1/2 throttle, the engines peak out at 4000RPM and just hold there like they're against the rev limiter.

Some background on the engines:
Both engines are basically new. Both engines run/idle and are making >130psi compression in all cylinders. One engine is a SBT reman the other got a new piston. I've rebuilt all the carbs, replaced the fuel filters and fuel pumps with the larger capacity dual feed ones. I removed the oil pumps and am premixing - currently it's 32:1 for break in and the smoke isn't bad. I've changed the plugs, but nothing changed.

The only other thing that it might be is the fuel is over a year old. It smells OK and doesn't see to have water in it. I'd think that if it were fuel, the engine wouldn't idle and would have plugged up the low speed jet.

Thanks!

 

[swill777]

I had 9 month old fuel that sat in my camaro, that destroyed my fuel pump, and even after replacing it, I had to siphon almost all of it out, and fill the tank all the way to get it to run right.
Just a thought... this was regular 87 pump gas with 10% or less ethanol.

 

[pincusa]

I had 9 month old fuel that sat in my camaro, that destroyed my fuel pump, and even after replacing it, I had to siphon almost all of it out, and fill the tank all the way to get it to run right.
Just a thought... this was regular 87 pump gas with 10% or less ethanol.

Thanks. I added 12 gal of fresh fuel to mix in the oil, so there is some fresh gas in there. I might try connecting the fuel pump directly to a gas can to see if that helps.

 

[scooper77515]

I hate to state the obvious, but do you have it in FORWARD gear? If in neutral, it will not go above 4000.

Sometimes the obvious solution is the best solution. So hope this is it for you...

 

[timmyboy76]

Scoop on right track, possibly, the rev limiter, thats built into the lever assy (pull assy out, you'll see a black box, with wires) might be stick'n, in which, even lever moved to F, button is closed...

 

[pincusa]

I hate to state the obvious, but do you have it in FORWARD gear? If in neutral, it will not go above 4000.

Sometimes the obvious solution is the best solution. So hope this is it for you...

Not the obvious to a new owner! That sounds like it might be it!
I am in neutral on on the trailer. I'll put it in forward and see what happens.

Thanks!!!!

 

[pincusa]

scooper77515 I'll buy you a beer if we meet!

Long story short, I put it in forward and it was the same deal. I pulled the shift levers and found that the switch on the direction lever was bad, so I just bypassed it. Problem fixed! Off to the water!

Thank you guys again!

 

[pincusa]

Doh!

As as I bypass the switch, the computer thinks it's in gear and won't let the starters kick in... So I'll have to fix it.

 

[scooper77515]

Well, glad we got you going in the right direction.

You can email that beer over to me, because I don't plan on making it to New York anytime soon :cheers:

 

[Gunsrunner]

:agree:To do a test you could just wire a switch inline, the rev limiter usualy stops the revs at a lower setting 3000rpm, thats why i'm not sure if this is your problem but then it's on both motors so there has to be a link.
When my stator went bad it would not let the engine rev past 4000rpm, i dont think it had the spark to get it past that.
I hope it's as simple as the neutral switch! Good Luck!!:cheers:

 

[pincusa]

It actually turned out to be two things.
The switch was bad - or dirty I should say. I cleaned it out with spray cleaner and now it's working again.
The other problem was the shift lever was sticking and wasn't moving the last 1/8" to close the switch. The buckets were up, but not all the way up. So even when the switch was working, it wasn't closed and wouldn't rev up.

It's all fixed now and both engines rev up past 4000RPM! Life is good! Thanks again for the help!


Just have to fix the last problem of the friction setting on the port throttle. I see the friction and position adjustment for the shifter, and also see the friction adjustment for the stbd engine. But can't find anything for the port throttle....

 

[Gunsrunner]

To adjust port throttle lever (inner lever), turn set
screw on center of pivot point of lever.
which is number 40 on this link.
http://partsfinder.onlinemicrofiche.com/seadooforums/Seadoo_oem/Seadoo_JB.asp?Type=13&A=24&B=12