theonlyrobertson
Cadet
- Joined
- May 31, 2003
- Messages
- 17
I have seen this problem in the forum and have the same symptoms. <br /><br />After open throttle running the engine develops a squeak similar to a noisy belt on a car engine. It tends to go away at idle and takes about 1 minute of open throttle running for it to develop.<br />The first time it happened I had just run about a mile at full throttle (5300 RPM). Now it happens running at part throttle. Ultimately, from what I have read, it comes from the engine leaning out too much.<br /><br />Here's what I have done so far:<br /><br />New water-fuel seperator.<br />New fuel filter (between the pump and carbs)<br />New primer bulb (Mercury OEM).<br />New diaphragm kit in the fuel pump.<br />New plugs.<br /><br />Running with an external tank tied in at the fuel line at the engine has the same results. This was tested after all the above items were done and should eliminate any leaks in the on-board tank and connections to the engine as the source of the problem.<br /><br />Other observations: Pee stream runs well and constant for full RPM range. Engine starts without issue. It idles rough and even makes sort of grinding noise every so often when idling in gear.<br /><br />I have set the carbs as follows: <br />Upper: 3/4 turn.<br />Middle/Lower: 1-1/2 turns.<br /><br />I tried +/- 1/8 turn in either direction with no improvement.<br /><br />I checked the cam/follower on the carb linkage. It has about .007" clearance. <br /><br />Question # 1.<br /> I'm not sure the purpose of the white line is since the follower rotates freely on the shaft at idle. What is this for and how is it used?<br /><br />Question # 2.<br />Something I have not seen in the forum is a discussion of the idle screw (it has a big label on it). It has a white plastic cap on the head of the screw to make it easy to adjust with your fingers and it appears to move the lingage that connects to what I think is the timing advance under the flywheel. What is the proper adjustment for this?<br /><br />Question # 3.<br /><br />Any other ideas what can be causing this noise problem assuming the carb and idle screw are adjusted properly.<br /><br /><br />Thanks in advance.<br /><br />Dale