Man, I hope not. You'd never get all four of them right. The two main needles on smaller V-4s were bad enough. But if you insist, I imagine the kit for the 6hp MIGHT work with some re-engineering.
Let me get a couple pics of them. I have looked at 66,67,68, 100 hp carbs and none of them have anything like mine. Instead of a plug on top of the jet it has what appears to be a packing nut and adjustable needle.
just like that but on a different set of carbs. I have the 4bbl carb on the 67 100 hp but with those main jets. Any idea where to start out with them? I have no idea what jet is under them. I was going to start at 1 3/4 and just make a few hot passes and read the plugs unless I had what I thought was a lean condition then I was going to 2 1/4 and read the plugs from there.
Why in the world do you feel you need to adjust the high speed mixture? As F_R said "You'd never get all four of them right".
As for plug reading, on engines with adjustable high speed circuits the mix was adjusted for highest RPM. Don't even need a tach for that. Our ears are wonderful for detecting a change in rpm
I did not install them I found them when the cowling came off. After looking to see if I could find them in the parts catalog and could not for a 100 hp I opened this question. As for tuning a 4 cyd engine with adjustable mains I see no problem with that other than time. If the high speeds were adjusted for the highest rpm which I am sure they were AT ONE TIME however if the loads change so do the fuel requirements as in if the motor is changed over to a different boat which is the case here. Sometimes the highest rpm is a slightly lean condition and the plugs do not lie but your ears may.
Loads change all the time, but that carb came with fixed jets, no adjustment available or needed. However if some one has messed it and installed an adjustable system you need to start out rich and lean it out. 2 1/2 turns out is richer than 1 1/2 turns. You might be better off by finding another carb on ebay and getting the jets out of it. In the days of High speed adjustments the owners manual said to adjust for highest RPM. Granted those were the days when 24:1 and 16:1 were used. Plenty of oil was there even with a slightly lean carb setting. With a 50:1 mix a lean carb could be risky. Might be one of the reasons OMC switched to fixed jetting on most engines just shortly before they switched to 50:1.
