Re: Carburetor jets 1979, V4, 100hp Evinrude--size?
Dhadley-Captain,<br /><br />A few years after I bought this engine new(1979 100 hp), I purchased 115hp jets and put into it, I split the carb in half and screwed the old ones out and the new ones in, it gave it alot of boost out of the hole and a little more top end(I was told that the only difference between the 85hp, 100hp, 115hp and the 140hp was the jets in the carburetor), all these particular motors are something like 3166 cubic inch centimeters each as far as size , I debated on 140 jets, but I was afraid of the gas consumption, anyway that is where the jets size come into this---Now the rest of the story. I took my motor in last year for a tune-up, it had a miss to it while idling, it had a cough to it, but the mechanic said I had a bad cylinder, the top ring on the top piston on the right side had curled up on top of the piston, I was told that on this particular model that the top ring was real close to the top of the piston and because I had run it for over 20 years, it had just given way due to stress, my block was to scratched up to be bored, I think you could of had it resleeved, needless to say, my mechanic supposedly found another block, he was suppose to install new pistons and rings, the new pistons were suppose to have a substantial space between the top ring and the top of the piston, about 1/4 inch,(something about Evinrude use to use the pistons that had very little room between the top ring and the top of the piston--they quit using this type around 1979-80)anyway, everything was suppose to be new except the crankshaft. I took it out several times when I first got it back and never got it over 30mph, the mechanic told me to run it easy to give the motor time to break itself in so after about 100 gallons of fuel in about a 8 month period, when I tried to open it up and see what it would do, it would top out at 36mph up on pad, it would go 42 to 44 before I had it worked on. I contacted my mechanic and he told me it probably needed adjusted and fine tuned a little, so after about 6 months of being put off, he finally told me to bring it in. He supposedly adjusted the timing from 24 to about 28(whatever that means) and he adjusted my throttle cable(he said it wasn't opening up all the way-lacked about 1/4 inch), so after about 2 weeks after I got it back I was finally able to put it in the water to see what it would do. Well it may have idled a little faster, but that was the only difference I could tell-still 36 mph, on the money. Now even though it starts like a top and shoots out of the hole like a rocket(I have a stainless steel power prop)it shouldn't be 6 to 8 mph slower.<br />I have suspicion that he found an old 85hp motor, tuned it up and stuck it on my lower unit and told me it was rebuilt and that was it, the jets were just the only way, with the exception of having another mechanic tear into it, that I knew I could figure it out. I'm trying to give him the benefit of the doubt, but I'm definitely not happy at all-something is wrong, wouldn't you agree??<br /><br />Thanks for your time.
