Ok, so i spent some time prepping the new engine for the boat – machining the flywheel and the head. I also replaced the fuel tank with an airplane tank to make sure water doesn’t get in again – it’s lighter too so that will help with balance of the boat. I even done a ‘double vent’ on the tank, the vent from the main tank goes to another smaller (2oz) tank to make sure water can not get in.
So, i got it all together ready for a run Sunday arvo but there was something strange happening with the engine. It started and revved lightly but with more than about 1/2 throttle it just sounded as if it was on a rev limiter. It’s hard to explain but it was like it was only firing every 2nd rev of the engine. I messed with the mixture screws a bit but it made no difference.
Some closer inspection has found what i think is the problem. It seems that the ‘key’ that keeps the flywheel in a certain spot in relation to the crank sheared off. I don’t know when it done this but that’s what i suspect the problem was since this is what sets the timing of the engine. It was probably really out.
The simple solution there is to swap flywheels, well one would think anyway… But this revision is keyed to the crank differently. This one has the key cast into the flywheel and is thicker by about 1.5mm. So, to use the other flywheel, i have to make a key and file out the keyway on the original flywheel (while trying to keep it symmetrical so as not to alter the timing). Oh what fun!
More to come…