91 johnson 40 horse 2 questions

[new_kid]

I have a 91 40 horse johnson and i want to know what the chances are that my tac in my boat is acurate or not and how to check and also wondering how to check the fluid level in the tilt and trim any help would be greatly appreciated

[marine_man]

With respect to the tach; is there something that leads you to suspect it's not correct?

Same thing goes for your trim & tilt fluid...

marine_man

[boatfixer]

The fluid should be level with the fill plug on the resiviour while the engine is tilted all the way up.

The easiest way to check the tach is against another tach, such as an inductive tach/timing light. I dont know if you have access to one or not. How far off do you think it might be?

[new_kid]

thank you for the info now i dont know what type of oil to use in the tilt and trim is it just hydrolic oil or something special and the reason i ask about the tach is because i am not sure if mine is acurate because it is an original with the boat that is a 1986 any ideas if it should be acurate or not? again thanks for any help

[marine_man]

I would suspect that your tach is accurate - if it shows you idling around 600-700 in gear, and doesn't top out beyond 5500 or thereabouts I think you'll be just fine.

marine_man

[boatfixer]

Use marine trim and tilt fluid