In my garage I have 3 engines a 76 135hp with trim and tilt, a 75 135hp (this turned out false) and most of a 73 85hp. I live in sweden and it?s hard to stumble on any 70s engines not completely spent so parts are scarce.
I?m trying to get the 76 135hp running but opted to buy a spare 75 135hp engine that was running but with a bad gearcase. When I took a closer look I saw the powerhead was of a newer kind and was bolted to the exhaust adapter with one bolt on each side missing since they dont line up. It also turned out to have bent watertubes so I had to tear everything apart. I checked the alignment of exhaust and water passages between the newer and older powerhead and they line up fine except the two bolts. I also spoke to my local dealer that has building these engines for ages and he said it?s no big deal if the two bolts are left out which is what I would have concluded to, of course I realize if it seizes on me anyone can tell me I told you so but I?m taking my chances and putting it back together.
As for the carbs I was gonna clean and check the carbs on the spare engine I?m using and quickly realized they where of yet another kind I hadn?t seen before with adjustable needles. I can see that the carbs have the same body and the dropping of the valves for later year models is just a development, BUT I just feelt there was yet another weird thing about this motor that I thought to be a genuine 75 135hp and that looks to be made from whatever was lying on the shelf.
I just wondered since I have no manual mentioning how to tune these carbs if I need to think of anything special with separate low speed jetting?
Also the mains looked at 56C to be small compared to my genuine 135hp carbs that has all fixed jets and 61C mains and made me think the carbs might come from a lover hp engine. I dont need peak hp at all I?m happy with a good running one but I?m curious.
I tried to guess what yearmodel and hp engine these carbs came from so I could understand best the "bastard" engine I?m hoping to run so I can diagnose any funnies. The engine ran before dissasembly and looks to be well built, compression was superb, .020 overbore and nice cylinders, no signs of overheat. Waterpump is overhauled, thermostat and new gaskets, water deflectors in good shape.
This will be my gamble to get some kind of spare engine for the season while I?m rebuilding my original powerhead so I?m well aware that the experiment might turn out bad but as long as there?s no leaks between adapter and powerhead and the carbs doesn?t add any trouble I should be fine.
That?s not the whole story but the most of it, any input? Who?s betting on a burned piston, blown gasket or perhaps 45 knots hour after hour? I?ll post whatever the results pretty soon I hope.
