1971 Merc. 165 inline 6
I am not sure how hot the rubber exhaust tube inside of boat is supposed to get but I think mine is a little warm. I can touch it for about a second before having to remove my hand and so far the engine has only been run at idle on the muffs, I have NOT yet water tested it at a higher RPM. The hot spot is on the side facing the front of the engine. The rest of the rubber tube seems to be at a cooler temperature and I have no idea why. When I took the riser off last year all of the passages were 100% clear, but maybe I need to check it out again?
1. Timing is correct, 6 degrees before
2. All the water coming in from the drive is going out through the exhaust and there is a lot going out at idle
3. Impeller is good and new, I have a clear inlet hose and it is full of water
4. idle mixture seems okay, at first it was lean and I enriched it which dropped the engine temp from 130 at idle to 120
5. Dwell is good
6. Engine seems to run great
7. No burning rubber smell
8. Riser was fine when I took it apart last year
9. Fresh water only
10. Open cooling
Ideas? maybe my riser is toast and isn't evenly dumping water out? This one really has me stumped. I would have never know about the problem if I hadn't been checking back there when the engine was running, but maybe it does get that warm at idle?
I am not sure how hot the rubber exhaust tube inside of boat is supposed to get but I think mine is a little warm. I can touch it for about a second before having to remove my hand and so far the engine has only been run at idle on the muffs, I have NOT yet water tested it at a higher RPM. The hot spot is on the side facing the front of the engine. The rest of the rubber tube seems to be at a cooler temperature and I have no idea why. When I took the riser off last year all of the passages were 100% clear, but maybe I need to check it out again?
1. Timing is correct, 6 degrees before
2. All the water coming in from the drive is going out through the exhaust and there is a lot going out at idle
3. Impeller is good and new, I have a clear inlet hose and it is full of water
4. idle mixture seems okay, at first it was lean and I enriched it which dropped the engine temp from 130 at idle to 120
5. Dwell is good
6. Engine seems to run great
7. No burning rubber smell
8. Riser was fine when I took it apart last year
9. Fresh water only
10. Open cooling
Ideas? maybe my riser is toast and isn't evenly dumping water out? This one really has me stumped. I would have never know about the problem if I hadn't been checking back there when the engine was running, but maybe it does get that warm at idle?
