I have a universal m18 700 hours. I run my engine at about 2000 rpms, but latly I've notice that it won't go over 2000 rpms, and I've notice an exess of soot on transom.My boat always has a little soot on transome,but I seem to be getting alot more since I won"t go over 2000.I treat my fuel and keep my fiters clean.The one thing I have'nt done was check the fuel pick in tank, some models had a screen on thr pick up. I was going to wait untill I haul out to check it,I don't want to open a can of worms and lose the rest of the sailing season. Any help would be great
- Status
rpm and soot
When my old Yanmar 2QM15 would do this it was because I had collected barnacles on the prop. A quick dive over with a scraper (and gloves) would rememdy that.
When my old Yanmar 2QM15 would do this it was because I had collected barnacles on the prop. A quick dive over with a scraper (and gloves) would rememdy that.
RPM
Your problem may very well be from running at the 2000 RPM level. These little diesels like to be run hard. Most say around 80%. When run slow and easy, like 2000 RPM, they have a tendancy to build up soot and carbon, especially in the exhaust riser. A down and dirty trick to fix the riser problem, damn I hate giving away my secrets, is take the raw water inlet loose BEHIND the strainer, attach a hose and run a gallon of straight muratic acid through the system. As soon as you run it through, put the hoses back on and flush with raw water. Then run the engine harder. The way I run my little Yanmar is as soon as it warms up, to push the throttle to the stop, run it for about 15 or 20 seconds wide open, then back off just a little. I never get any soot stains on the transom, and the engine never gives any problems. It is a 1980 model, 2QM15.
Your problem may very well be from running at the 2000 RPM level. These little diesels like to be run hard. Most say around 80%. When run slow and easy, like 2000 RPM, they have a tendancy to build up soot and carbon, especially in the exhaust riser. A down and dirty trick to fix the riser problem, damn I hate giving away my secrets, is take the raw water inlet loose BEHIND the strainer, attach a hose and run a gallon of straight muratic acid through the system. As soon as you run it through, put the hoses back on and flush with raw water. Then run the engine harder. The way I run my little Yanmar is as soon as it warms up, to push the throttle to the stop, run it for about 15 or 20 seconds wide open, then back off just a little. I never get any soot stains on the transom, and the engine never gives any problems. It is a 1980 model, 2QM15.
Growth on your shaft
Rick - any way for you to check the growth-condition of your bottom, shaft and prop? I had a new baby this summer (she is sitting right next to me
) and our boat was not used for 6 weeks during peek-growth season in the creek I keep her at. When I finally got her out for a ride I had a similar problem. When I revered her up soot was pouring out...you get the picture. Good luck! Rob
Rick - any way for you to check the growth-condition of your bottom, shaft and prop? I had a new baby this summer (she is sitting right next to me
) and our boat was not used for 6 weeks during peek-growth season in the creek I keep her at. When I finally got her out for a ride I had a similar problem. When I revered her up soot was pouring out...you get the picture. Good luck! RobIn Gear?
Do you have this problem only when in gear? Can you rev the engine higher in neutral? If the the problem only happens in gear, then your problem is a fouled prop or bottom. If it happens in neutral, then its an engine issue.
Do you have this problem only when in gear? Can you rev the engine higher in neutral? If the the problem only happens in gear, then your problem is a fouled prop or bottom. If it happens in neutral, then its an engine issue.
Sorry G
But I must disagree ;-). An engine will operate entirely differently when a load is applied. I have a long history of building and rebuilding engines. I have seen engines that will rev to 3000rpms in neutral but not budge past 1500 under load. This is a telltale sign of "air" not being pumped through the engine such as a clogged exhaust. Tim R.
But I must disagree ;-). An engine will operate entirely differently when a load is applied. I have a long history of building and rebuilding engines. I have seen engines that will rev to 3000rpms in neutral but not budge past 1500 under load. This is a telltale sign of "air" not being pumped through the engine such as a clogged exhaust. Tim R.
- Status