1999 100 HP Johnson

[2whalers-1 motor]

First time here. I am currently restoring two 60's vintage Whaler Nausets. I have one almost done and the second one I bought has 99 Johnson 1oo HP commercial motor. Since I know nothing(yet) about Outboards I thought I would start here.
Is there anything I should know about this particular engine? Has anyone here ever had one or can anyone tell me anything about MPG, VRO, optimum prop etc. I will,eventually read everything I can find about the engine from the Mfg. but users can tell me a lot more. Thanks for any responses. Chris K

 

[ugadawg187]

Re: 1999 100 HP Johnson

your prop selection should be one that at wide open throttle (WOT) your motor is hitting its peak rpm range. Say the peak range on your motor is 5500 rpm's then at WOT thats where the rpm's should be & not more or less. You have to factor in the weight of the boat. Say a 100hp on a 15ft boat with a 19 pitch prop may turn 5500 rpm's as to where on a 20ft boat it may take a bigger 23 pitch prop to turn the same amount of rpm's. I would say your MPG depends on how you have your boat & motor set up along with how hard you run the motor. Hope this helps.

 

[tashasdaddy]

Re: 1999 100 HP Johnson

Boats are no measured by MPG, but GPH Gallons per Hour. universal rule of thumb is 10 gallons per hour, for each 10 horses, at wide open throttle.

that is a super great motor, as all are when proper maintained. Service Manual is only available thru dealer or BRP.