So the full run down is I bought a boat with a 1977 Evinrude 115 on it about a year ago. After two weeks on the water the bottom bearings came loose and blew a hole out the side of the crankcase/block. With Evinrude the 85 and 115 are the same motor except for a few carb tweeks and the heads are a bit different sizes. So we bought an 85 block and rebuilt the motor. Cleaned the carbs and put it back together. Where I am currently is that the boat will run when good at higher RPM's. But when it drops to lower RPMs to say put it into gear/idle. It wants to give out. So far I have cleaned the carbs thoroughly. I also adjusted the idle so it has plenty of gas at lower RPM's. Ive done a link and sync to ensure the timing advances properly. We also thinned out the oil in the gas becayse we noticed it smoked a lot which indicated too much gas.
In the water the boat will run decent at lower RPM's but only if the motor is trimmed almost out of the water. Which to me indicates it doesnt do well with a heavy load on the prop. Once the boat planes out and is running it does great and will reach around 33 mph. Is there anything else I could possibly be missing from a mechanical end? Fuel pump seems to be clean as well. Any guesses are more than welcome.
In the water the boat will run decent at lower RPM's but only if the motor is trimmed almost out of the water. Which to me indicates it doesnt do well with a heavy load on the prop. Once the boat planes out and is running it does great and will reach around 33 mph. Is there anything else I could possibly be missing from a mechanical end? Fuel pump seems to be clean as well. Any guesses are more than welcome.