Simple Evinrude Question

[TheFormerlives]

This is a simple question which I can't find the answer to anywhere. All I need to know is the max RPM range for a 1988 100XP Evinrude. I was told 4000-5000 by one guy and 5000-6000 by another. Thats a pretty big difference.

Thank you.

 

[jchristi]

Re: Simple Evinrude Question

5500 for most two strokes, I cant recall but it may be stamped on the plate on the transom mount.

 

[F_R]

Re: Simple Evinrude Question

The 1988 V4 crossflow engines were 4500-5500. The V4 loopers were 5000-6000. I believe yours is a crossflow, right?

 

[emdsapmgr]

Re: Simple Evinrude Question

It's a crossflow. You've gotten good information. You should prop the engine to run at the top end of that factory recommended range, or 5500-5600 at top end.

 

[TheFormerlives]

Re: Simple Evinrude Question

Thanks guys. If my tachometer is correct then I am currently turning a 17pitch stainless prop at approximately 5200 or 5300 RPM's when fully trimmed at WOT.

If the max RPM range was 4-5k then I was going to up a pitch in prop and hopefully gain some speed. But it seems like I'm getting about the best performance I can right now with 43mph (GPS'd) on a heavy fiberglass boat.

 

[emdsapmgr]

Re: Simple Evinrude Question

If you are going to change props, you may mean that you want to go down in pitch, not up. If you go up to a 19 pitch, you will loose about 300 rpm, winding up at around 4900. At those rpm's, the engine is considered lugging. A 15 pitch should gain you 300 max rpm, and give you 10% more torque thru the whole rpm range.

 

[larryg]

Re: Simple Evinrude Question

4500-5500

 

[TheFormerlives]

Re: Simple Evinrude Question

What I meant was that if the max RPM range was 4000-5000 then I would go up a pitch in prop which would drop me 200 or 300 RPM's. I'm currently at about 5200 (just had it out today) and that would put me in the appropriate range as well as gaining me speed.

But alas! I'm right in the middle of the appropriate range! I was hoping for more speed but oh well. Thanks for the great responses guys!

 

[emdsapmgr]

Re: Simple Evinrude Question

Go down one prop size with your prop. Gain holeshot and 300 rpm, up to 5500. You will like the results. You want to prop that engine to run in the upper end of the "normal operating" range.