a buddy of mine just picked up a 13' valco with a 1969 25hp johnson of craigslist. he was told that the engine hadn't worked in two years but came free with the boat. the engine had an aftermarket kit with an electric starter that he was told was never used and not working.
i took the engine and rewired the electric starter and got it working. then i did a compression check and although somewhat low, they were both within 5lbs of one another. i then took off the carb and put a new kit on it, then changed the plugs and fuel filter and hit with some starting fluid cranked it over and it started right up.
it blew out a ton of black gook in the barrel and was idling high and not spitting out any water. i serviced the lower unit and put in a new impellar and clean out the top end of tubing and started it back up. after some additional throttle linkage adjustment and lean adjustments i got it idling and spitting out water.
after that we let it run to get all the gook out and took it down to launch ramp for a test drive. the engine runs pretty good, but it really doesn't seem to have much power. with one person on the light little 13' valco is almost planes out, but with 2 people it barely does 7 mph and its a 25hp.
i put my kicker 9.9 off my arima on that boat and go faster than with the 25hp. i don't know how to adjust the timing on this motor but it seems to be running fine and i have the throttle adjustments to flat out maxed.
i then took out the plugs and clean them, even cranked it a few times to get any other gook out of it and put it back together.
although i do not think this has much to do with this problem, the prop on this motor has some damage and seems very small for the engine, what pitch would be recommended for this engine to get better speed?
any help with ideas to get more power would be appreciated. please chime in.
thank you in advance for any assistance you can offer.