[lowdouble]

I managed yesterday to clip some submerged rocks with my old engine.
When I later put the engine into reverse the propellor nut unscrewed and both the nut and the propellor sank.

The engine is a mariner 9.9 2 stroke, 1986 model, serial No 9487998, 3 blade aluminium propellor,
I want to order another one but am unsure about the pitch? (what affect does it have). And the diameter of the prop that I need?

Please can anyone help me.

Big Andy

R.O.Ireland
.

[luv2b0at]

If you were unhappy with the performance before now, a different prop may help. If you were happy with how it worked, just order OEM part. The place you order from should be able to tell you what was original.

[lowdouble]

Thats a very honourable CV you have there luv2b0at.
does a higher number pitch mean the boat is to go faster than a lower number pitch ? or vica versa.

[steelespike]

While there may be a "standard"prop the prop you had would depend on what boat you have it on and may be different than "standard" If you give us the details on your boat and typical load we should be able to get you in the ball park.

[lowdouble]

Thanks for the info mate, I use the engine on either my 16ft sea nymph or on my 19ft lake boats, (fiberglass rowing boats with hardwood seats and trim) with displacement hull. the engine doesnt "rev out" on either boat and only gets up to a maximum speed of 8.4mph (gps). There is still 15 percent more throttle available but all it does when used fully is to make the engine louder, not the boat faster.

[steelespike]

Is the Nymph a bare bones utility or loaded up with floor, livewells etc.
Are you sure the motor is running on both cylinders?I would think that carefully setup and lightly loaded the 9.9 would plane the Nymph somewhere between 12 and 18 mph.Even if a deluxe.I think the 9.9 came with a 8" pitch.Not having any performance specs Based on your boats I would try a 7" pitch,perhaps a 4 blade.
The displacement boats would probably perform best in the 6 to 9 mph range regardless of how fast the motor will push it.You should borrow or buy a tach so you can check the rpm it is important that the motors health that it operates within its rpm range.A tinytach is reasonable and easy to install.

[lowdouble]

Yes it is a bare bones Nymph, its true what you say about the lake boats, they only go the same speed with my 5hp mariner as they do with the 9.9.

once again thanks for replying.

Big Andy