40 hp jhonson q's

[twintrades]

I have a new to me "old" jonson. I dont know the yr but its green and white. Im just trying to find out if it needs a new prop. THe on on there dost have any markings and oddly enuf it seems like the blades are pretty skinny....

Anyway im wondering how do i find out what rpm im running at? it has not tach or anything ???

 

[YoungMind]

go to an auto parts store and get an induction tach, or buy a tiny tach

Also the model and s/n should be on a plate at the transom bracket. that will help determine the year

EDIT: If the prop has no numbers stamped on the outside, then the numbers should be on the inside around the hub, which would be under the prop nut.

 

[pckeen]

Post some pics of the model you have here, and that may help identify it, so you can track down some basic information on the engine. If there are no serial number or model number markings on the transom bracket, open up the cover and look for a silver, nickel-sized plate on the powerhead - this will give you the powerhead serial number, and Johnson or a local mechanic should be able to track down the year of the motor.

 

[steelespike]

Last year for a green and white Johnson was 55. And if its a big one it's a 25.