97 200HP Ocean Pro - erratic idle RPM

[dingbat]

Ran it yesterday for 10 hours w/o any noticeable problems. Trolled for 8 of those hours w/o any symptoms. Go out this morning to flush it and its acting up on the hose.

Start it up, it sits at high idle @ 1500 rpm then drops down to it's normal 1100-1200 RPM. It will sit there for a couple of seconds then build back up to 1500 RPM, stay there for maybe 10-15 seconds then drop back down to 1100-1200 and start the process over again.
I'm thinking a sticking float or needle valve? Nothing noticeable just looking at the carbs. Any thoughts on how to narrow down the problem?

 

[jonesg]

Re: 97 200HP Ocean Pro - erratic idle RPM

Idle speed is set by ignition advance , check the roller is still intact on the idle pickup cam lever. Its a sleeve that establishes correct distance between lever and cam, they split and fall into the lower pan, look for it there.
Actuate throttle and watch the mechanism to see if its getting hung up when returning to idle.

 

[dingbat]

Re: 97 200HP Ocean Pro - erratic idle RPM

Idle speed is set by ignition advance , check the roller is still intact on the idle pickup cam lever. Its a sleeve that establishes correct distance between lever and cam, they split and fall into the lower pan, look for it there.
Actuate throttle and watch the mechanism to see if its getting hung up when returning to idle.

Roller still there and throttle is set 0.005" off the roller per specification.
Acts like Quick Start is dropping in and out.

 

[jonesg]

Re: 97 200HP Ocean Pro - erratic idle RPM

Roller still there and throttle is set 0.005" off the roller per specification.
Acts like Quick Start is dropping in and out.

Its also possible the powerpack is going south, I don't know any test for that except disconnect port temp sensor white/bl wire , then check timing at 900rpm is at 4 degs BTDC with timing light. Engine has to be above 105 degs for test.

REconnect wh/bl wire and check quick start releases to 6 ATDC.

If not, test temp switch.

high idle could also be a lean condition, air leak someplace in the fuel supply side, clogged filters,or sticky anti-syphon valve at tank. But I think you'd notice the bulb deflating on that one.