25hp to 35hp with carb swap???

[wjhuskey]

I have a 1989 Johnson 25 hp and the weight of it is perfect for my little 14ft 1961 vintage runabout. The boat originally came with a 40 hp so I wanted to ask if it's true that all it takes to make my 25hp a 35hp is the carb?
Yes I know I won't be able to tell much of a difference - only 1-2 mph and worse fuel efficiency but like I said, the boat did originally come with a 40 hp and 40 hp's nowadays are heavier than the ones in the 60's. Does it just take a 35 carb or different intake, prop too? Thanks in advance.

 

[oldboat1]

Get a '61 Lark.

 

[matt167]

You need the intake and carburator from a 30/35hp and then you need to time it to the 30/35hp specs and you'll also want to re prop it. It does not cost much. $100 for a carb or so, and $30 for the intake

The 35hp lost 5hp in 1986? due to the prop vs crank rated hp change. They were 30hp rated after that.. You can use a primer carb, or a choke carb depending on what you have found. a 35hp choke carb does not magically give you 5 more hp over a 30hp primer carb. Either motor will give you 30hp at the prop

An old Johnson/ Evinrude Big twin 40hp are great but very thirsty engines

 

[oldboat1]

Owned a number of '50s and '60s 35s and '40s. Maybe yours were set too rich?

 

[racerone]

An engine that uses a bit more fuel with no other expensive upkeep can be a better deal.----Drove a 1967 Caddilac at one time.----Used a lot of fuel but I could maintain / fix it myself.----Not so with the vehicles I drive today.

 

[matt167]

An engine that uses a bit more fuel with no other expensive upkeep can be a better deal.----Drove a 1967 Caddilac at one time.----Used a lot of fuel but I could maintain / fix it myself.----Not so with the vehicles I drive today.

I tend to agree. I drove a '74 MGB daily for 2 summers. One time it dropped a cylinder, and I determined it to be compression loss. Got it home, adjusted the valves and had it back out the next morning. Other than a squealing belt from time to time, it was one of the most reliable vehicles I've ever owned. It did get great mpg though


But an Johnnyrude 20-25-30-35 twin isn't a bad engine