2001 johnson jet drive 30hp

[Snake River King]

I have a 2001 johnson 30 hp jet motor and when I hooked up the tach on it, it said that at full throttle I was running 2800 rpm? does that sound right? The motor sounds like it is reving out but i would of thought it should rev higher? I have it mounted on a 1648 jon boat and its rated for a 35hp and I can get the boat to go about 20mph, does that sound good? thanks for the info smart boat people!!!

[hydro]

Your tach is reading 1/2 the rpm that the motor is turning. Are you sure it is for a 2 cylinder motor and not a 4 cyl? Is there a switch on the tach for the # of cylinders? Do you have the instructions/wiring diagram?

I would think that 20 MPH with a 30 HP jet on a 16' boat is pretty good!

[Snake River King]

i have the switch on the back of the tach and its set on 2 cylinder, maybe something is messed up with the tach..... but your right i didnt think about it 2800 x2 5600 rpm which is about right i would think

[marine_man]

Is it set to 2 cylinder or 2 pole?

Try the 6 setting...

marine_man

[Snake River King]

ok i will try that, on the back of the tach it says 1 2 3 4 5 6 and your right that is pole sets

[marine_man]

I'd keep adjusting until you get a rpm reading at idle (800 in neutral) that makes sense, then see where your top end is.

marine_man