Restricting outboard engines

[Amy]

I have to limit my outboard engine to reduce my boat top speed to less than 17kts? The engine is a 40hp mariner, tiller controlled.

Ideally the limiting has to occur inside the engine. Any advice welcomed.

Amy

[Poly]

I have no idea how technically minded you are or if you can bodge something together yourself. if i was trying to do this i would be fabricate a little "stop" to prevent the throttle cable travelling fully under the engine hood. But I would also look at swapping props first of all - as if you have to limit your top speed you might at least increase acceleration with a finer pitched prop - and use the "throttle stop" to prevent it over revving.

[willk]

I'm surprised and delighted that your 40hp tiller outboard actually takes your 6 meter Avon/Northcraft rib to 17knots without restriction! What make/model is it?

sorry - Mariner, must remember to read all of these posts!

[willk]

and welcome to RIBnet - compatriot! Really, I'll have to focus....

[Slaphead]

If you're having to limit the top speed is it for insurance reasons?
I would have thought downsizing to a smaller outboard would be the answer.

[nickd]

Could the prop be changed so that it cannot run faster than this?
Nick.

[nickd]

Could the prop be changed so that it cannot run faster than this?
Nick.

Oops..

Originally Posted by Polwart

.......But I would also look at swapping props first of all - as if you have to limit your top speed you might at least increase acceleration with a finer pitched prop - and use the "throttle stop" to prevent it over revving.

ND

[Locozodiac]

Originally Posted by Amy

I have to limit my outboard engine to reduce my boat top speed to less than 17kts? The engine is a 40hp mariner, tiller controlled.

Ideally the limiting has to occur inside the engine. Any advice welcomed.

Amy

Hola...

If it's a 2 cylinders, gear tiller 40 HP Mariner, the fastest thing to adjust to limit speed will be : loosen nut counterclockwise some mm, turn clockwise some mm the Stopper A bolt so to limit the tiller/carb advance so does not reach wot (wide open throtle, will be a matter of adjusting to the desire speed you are looking for with a apropriate instrument/gauge. Do not move anything else, hold still with a screw driver the stopper bolt A and adjust/tight the nut clockwise when finished.

See if you Mariner has the same type Stoppers as photo.
A(Upper) for WOT


Happy Boating

[Poly]

Originally Posted by nickd

Could the prop be changed so that it cannot run faster than this?
Nick.

Oops..

ND

Possibly - but the risk then is that it will over rev and then go bang - so you may need to consider a mechanical stop on the throttle anyway.