waterone1@aol.com
Lieutenant Junior Grade
- Joined
- Oct 10, 2004
- Messages
- 1,235
There have been several post's lately regarding poor performance and lower than normal RPM's at WOT(Wide Open Throttle). Sometimes it takes several questions to get to this, other times it comes up right away. Besides prop pitch, ignition system, engine compression, etc. One of the first things to check and or replace is your fuel filters !! Besides the large canister type water seperating filter, there is another filter in most engines that is often overlooked. Some of the other guys on here know where they are on other engines, but on most late 80's to early 90's Mercs with the Rodchester Carb they are in the fuel inlet at the carb.<br />Speaking from past experience, if this filter becomes partially clogged, the engine may start fine, run fine at partial throttle but will either "fall on it's face" or simply not achieve rated rpm's at full throttle. It can miss or run extremely rough at full throttle or simply not get the max rpm's.<br />While I have not directly seen this happen (feel free to correct me on this) it would seem that prolonged operation of an engine at full throttle with a partially clogged filter (lean mixture) would lead to engine damage and burned valves.<br />Since we cannot hear, in most cases,the signs of a lean mixture (detonation, pinging, etc.)in a boat, I would suggest one of the first courses of repair for high rpm difficulties to be checking and replacing the fuel filter. What do you think guy's(and lady or two)?
