Posted by John on December 21, 2003 at 20:16:47:
In Reply to: How to Justify the A-4 Engine Rebuilt Job? posted by leon on 16:13:48 12/20/03:
Your comment that the engine speed apparently increased without affecting the boat speed sounds like a reversing gear adjustment problem, although why it would get out of adjustment if it was not included in the rebuild is curious. Normally you look to things that have been changed when diagnosing a post-repair problem. It is fairly easy to tell if the reversing gear is slipping, much like it is very obvious in a car when the clutch is worn out. It helps if you can see the propeller shaft, but if not you should still be able to tell. Try this:
1. Increase throttle very slowly, trying to get the boat speed up gently. Note the RPM where it the boat speed stops increasing. The engine speed may suddenly increase at this point.
2. Do it again, but this time increase the throttle very quickly. If the reversing gear is slipping, it should do it immediately, certainly at a much lower rpm than when you went slowly.
Note - The reversing gear is very easy to adjust. If you change your own spark plugs, you can do it yourself. Invest in a copy of Don Moyer's (moyermarine.com) manual. It will save you a lot more in mechanic's bills and gives very good directions on the adjustment process. If you feel you must pay someone else to do it, ask them first for an estimate. If it is more than about one hour of time, they either have no idea what they are doing or they are ripping you off.