carb swap

Somebody school me..... All the specs that I find in the manual are the same for the carbed 4 strokes in the 75, 80, 90, and 100 class (bore, crank, valve clearance, etc.) Can we put 100 carbs on a 75?

Re: carb swap

The 2003 F75 that I looked at has one fuel pump, my 1999 F100 has two.

Re: carb swap

did you check the bore hole on the intake probably different

Re: carb swap

No, I haven't had a 75 apart to compare.

Re: carb swap

Well, I had an in-op 1999 F80 donated to me for parts. I took the carbs off of my 1999 F100 and measured with digital calipers and compared with the F80. The intakes are exactly the same size. The stamped part numbers on the carbs are different and both cylinder heads just have the 67F stamp on them. That's something if all of the parts are interchangeable from the 75 to 115 other than the carbs. Now I'm trying to decide if I want to just bolt my complete F100 power head onto the case from this F80 and see if my water and oil leak is fixed or just take guts out of my F100 and build up the F80's block and put my F100 carb stack on it. There is no corrosion or damage to the block from the F80, It suffered the over-propped rod failure and needs a crank and connecting rod. I think that my power head from the F100 is fine. I had the cylinder head welded and milled. And the compression on the cylinders is perfect.

Re: carb swap

Be careful about modification posting. If the owner's boat is rated for, say 80hp, and you give info about how to change it to 100hp, and an accident happens, YOU are liable for damages because YOU told him how to do it. If you're in an area where the EPA "sniffs" exhaust, and his engine is way out of specs, he'll get a $5,000 fine, but he has recourse to YOU. Modifications used to be fun until the legal-eagles got involved.

Re: carb swap

I'm getting my F100 usable with an F80 block. They all have the same numbers and my outboard will still have the F100 cowls. I guess that the same trouble could come from dealerships putting a jet drive on a F115 and throwing an F80 cowling on it. Exhaust sniffers will find F115 emissions coming from an F80 jet. Who would be held responsible if an F80 jet owner put a prop unit on it and his boat was rated for 80 HP..... I'm sharing what I've learned about mixing parts that are the same throughout models; not re-porting carb jets or modifying intake and exhaust manifolds. IF YOUR BOAT IS RATED FOR A MAXIMUM HP, DO NOT MODIFY YOUR MOTOR TO EXCEED THAT LIMIT. DO NOT CHANGE YOUR CARB JETS TO ANYTHING OTHER THAN WHAT THEY ARE SPECIFIED TO BE EITHER. Thank you for pointing out liability issues, I appreciate being looked out for.