surging rpms 787

[gcha1727]

Im trying to work the bugs out of this 98 challenger 1800 I recently bought. I had it on the water today for the 1st time. My L motor occasionally likes to go from 4k rpm to around 6.5. The raves were way overcut in the past...Im not sure why but I havent replaced them yet. Could that be the cause or is there more to look into??? Also my R motor which just had a top end rebuild doesnt want to go much past 4k. I didnt want to push it to hard during the breakin period but was trying to get short bursts in a little beyond 4k. I have been finding info on this site relating to this prob but any additional info would be appreciated. Thx

 

[WAJetboating]

On that engine that won't go very high on RPM's...

You say it recently had a top-end rebuild. When you took it out, did you record the carb linkage positions and sync? Are you certain they're back where they belong? If it runs just fine but won't go to high RPM's even with WOT, perhaps "WOT" isn't as "wide open" as you think.

 

[gcha1727]

Yes it does appear to fully open. I was reading another similar post that said to pull choke at 4k to determine if its a fuel or motor problem. Hopefully I can get it back on the water today to see.