I have a 35 GTR CC, purchased in February. Motor is completely stock. The motor has around 16 hours on it. The past couple of times I took the boat out the idle speed was not consistent. It would idle over 2000 rpms sometimes and less than 900 rpms the next time. I checked the idle adjustment screw and there were no apparent issues. I could set the idle to 1200-1300 rpms then after speeding up the motor and then subsequently returning to idle the motor would be idling anywhere from 900-2000 rpms.

It was around time to perform the first service so I decided to get that done and try to figure out what the problem was with the idle speed. Could not find an obvious problem with the carburetor or governor linkage that would cause the inconsistent idle. Decided to perform a compression test. Compression on both cylinders was ~150 psi. I then performed a leak down test. During leak down test the starboard side cylinder pressure dropped from 90 psi supply to ~86 psi on the cylinder side gauge. On the port side cylinder the cylinder side pressure gauge indicated 72-74psi and air could be heard escaping from carburetor. I am assuming the intake valve is not sealing correctly. What is an acceptable leak rate? Could this be the cause of my idle problem also? The intake valve seats correctly sometimes?

During some of my research I found deadbirds instructions and pictures on how to adjust the idle and set the governor. I found that my GTR does not have a spring attached to the governed idle tab as shown in deadbirds pictures.

That spring should be there it could have fallen off.

What was the question cause your avatar got my attention right now

50hptiller, So there is no allowable leakage. Any air leaking through the carburetor would require a valve job. That is not what I was wanting to hear.

Gator tail no longer installs a spring at the governed idle tab? I have a center console, I wouldn't think that small spring could break the throttle handle.

I did not say the springs are necessarily required. From the information I found (deadbirds post on how to set the idle and governor) my motor does not have the springs shown in the photos. Given the response from westendangler, GT at some time in the past also installed the springs or left them installed.

Since the motor is still under warranty and with the result from the leak down test I am just going to bring it back to gator tail and let them sort it out. If it was simply an adjustment I was going to do it myself instead of having to spend the time and money to bring to back to GT.

The allowable leak is anything less that 40% (accordingn to Briggs and Stratton).


I think that Calen does all of Gator Tails warranty work (or so he has told me). I'd bring it to him to have him process a warranty claim, and maby you could talk him into doing some port work too, while he has the heads off.