Re: Classic 50 just wont go
Reving it up in the drum, unfortunately, doesn't tell you much unless you have really experienced how these engines run in different states of failure. For example, it will sound almost fine when these engines are running on only 2 of 4 cylinders. Since there is no or little resistance (engine in neutral or from exhaust air mixed in water in drum), they will rev right up and zoom past redline. <br /><br />The merc classic 45/50hp engine depending on which year in the 80s is a great engine. I am the original owner of a 1985 50hp. <br /><br />My engine spent part of its life on a 20' pontoon. It would run 15 - 20 mph depending on load and conditions. <br /><br />1) Check for spark on all cylinders<br />2) Check to make sure it is getting fuel through both carbs<br />3) Check compression if none of the above. <br /><br />1 and 2 are quick and easy checks. It is possible that you have the wrong prop, but your symptoms sound like a little more. <br /><br />Common problems in this engine include:<br />- Power packs start to fail and engine runs on less than 4 cylinders. Test for spark on all cylinders. You can pick up a cheap test light at any auto parts store (place it next to the spark plug wire while the engine is running). <br /><br />- Like any engine of this age, the carbs get gunked up over time and can use a rebuild. After a rebuild or a thorough cleaning, I have had the float stick on one of the carbs resulting in fuel flowing through only one carb. Again, the engine will miss on 2 cylinders. You can easily see this by looking down the throat of the carbs while quickly manually advancing the throttle (you should see droplets of fuel coming out of the stem in the throat). If this is the condition, you don't want to run the engine too long because it is not getting a fuel/oil mixture to parts of the engine.
