Trojan Boat Forum

I`m a new owner of this boat and the first few voyages were fine. Now the port engine ( LM 318 ) revs up fine in neutral but under load will not exceed 2000 rpm. The boat is now blocked for winter storage and I can see there were lots of weeds on the prop, but no more than were on the starboard side which runs fine. I removed the air breathers before my last trip and soaked them in gasoline and blew them out with an air hose . This made no difference. Any suggestions?

One possibility is the spark advance, which is controlled by centrifugal weights balanced by a pair of springs inside the distributor. These are succeptible to corrosion. As the rpm increases, the weights rotate against the springs advancing the spark. You can test the advance by putting a timing light on the engine and reving in Neutral. The spark should advance about 25 degrees from idle to 2500 rpm. The advance is independent of load. It only depends on rpm. If the advance looks jittery as the engine revs, or only moves a few degrees then take the distributor to an ignition shop where it can be re-curved for a modest price (maybe $60). Other possiblities include carburetor issues, low compression, weak spark (wires, coil or distributor). The discussion board at http://www.marineengine.com/cgi-bin/discus/discus.cgi is an excellent place to get help from people more experienced than me on this kind of issue. (it seems to be offline tonight for some reason, but it should be back soon)

Thanks once again Chucka. Your suggestions and references are very much appreciated.
don

One more quick obvious thing to check is the fuel separator.
Good Luck,
Chuck