WOT Rpm??

[skyguy59]

1972 100 HP johnson. In what range should the motor be at WOT? The Plate says 4500-5500. The Local OMC guy says don't turn the motor faster than 5000 cause its old??? What range should I shoot for to keep the motor happy?<br /><br />TIA<br /><br />Russ In Texas

 

[ob]

Re: WOT Rpm??

I'd prop it to turn a solid 5500 at wot with a light load aboard.Once the boat is on plane ,the engine isn't working as hard and 500 rpm isn't going to hurt a thing.Propping it too steep will lug it otherwise at any throttle setting.

 

[ledgefinder]

Re: WOT Rpm??

Ditto what OB says - at least 5500 with you alone in the boat (and find a new "OMC guy"). <br /><br />That motor can sit at 6000rpm 24x7, where lugging it with today's gas can gum up the rings. Spinning & light load keeps the motor happy. Sustained 6500+ can lead to fatigue of the (stock) metal reeds on those V4s, I am told.

 

[skyguy59]

Re: WOT Rpm??

Thanks guys, I'll shoot for that. Might need to add an inch or so to the prop.<br /><br />Russ In Texas

 

[DES]

Re: WOT Rpm??

someone will throw a fit I'm sure, but 6000 with a light load is "Proper" for set-up. you want close to 5500 when loaded.