food for thought

I keep seeing that yall are changing out your carbs to larger hp models, but never mention changing out your exhaust tuners(exhaust pipe). Do you realize that whats goes in the motor must come out? Saying more air/fuel is going in due to having bigger carbs but its not coming out of the motor as fast due to the diameter of the pipe being smaller.

I know i could never get my 40 Tohatsu to run right with 50 horse carbs until i broke down and changed the exhaust out to a 50 horse piece.

You are correct, however many of the engine families that we talk about only have one option available to them. Other engines, such as the OMC 9.9-15hp have a megaphone option available depending on the year. Still other engines that get the carb change were designed as a higher horsepower engine and restricted by a carb. Some of the mid-range horsepower engines require a cylinder and crankcase change due to different porting to fully realize higher horsepower.

I swapped out my 25 carbs for 30 carbs on my 2000 Johnson; works like a dream. I agree with you that what goes in must come out, and I checked and cross referenced just about every part between a 25 and 30 hp. Virtually every part was indentical; intake, exhaust tube, driveshaft, I came to realize the only difference was the carb and the stickers. Worked for me.

But, while it's a possible upgrade on some engines, I highly suggest that anyone thinking about doing it does their homework first, making sure that they cross reference the models to see what changes and what stays the same.

lucky yall.. my tohatsu is a 40/50 block tuned down to a 25 with carbs and exhaust, made for running refuges with a 25 hp limit

Fastcajun is yours a Mega 25? Some people I've talked to say that's the " Holy Grail " of 25 hp. motors. It would probably be a good motor to make a 25 Hp Jet out of. Todd

lucescoflathead said:

Fastcajun is yours a Mega 25? Some people I've talked to say that's the " Holy Grail " of 25 hp. motors. It would probably be a good motor to make a 25 Hp Jet out of. Todd

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yes it is a mega 25. they only imported 145 of them in 2 years and most came to south La. saw one guy sold one for 6k in boxes not even running last year. i paid 400 for mine and im tired of it.
how would you make a jet out of it? im always up for something new, even though it wouldnt last long in our mud.