2000 Mercury 40ELPTO, 2 cyl, 2 stroke, low rpm at WOT problems.

[Suctoes]

Hi everyone.... Well I'm new here and could not find a thread relating to my problem so here goes.

I just purchased a 1996 stratos 258, 15'-6" fiberglass bass boat with a 2000, Mercury 40ELPTO, 2 stroke, 2 cylinder motor. The prop is a 13 pitch. I took the boat out to the river and it starts great, seems to idle ok "does kind of woap woap woap woap at idle." but when I took it to WOT it would not get even close to plane and would only turn about 3500 RPM.
I don't doubt the rpms because motor sounds no where close to revved up, and my butt says we were only doing about 20MPH.

1. What is the first things to check out?

2. What else could cause this? Anything that I could check with a DMM?

Thanks for any replies!

 

[Suctoes]

Another question......

Another question......

Anyone have a recomendation on spark plugs? It has champions in it now.

 

[Suctoes]

Re: 2000 Mercury 40ELPTO, 2 cyl, 2 stroke, low rpm at WOT problems.

Added seafoam fuel treatment today, Anything else I can try before I put it back in the water?

 

[Jeep Man]

Re: 2000 Mercury 40ELPTO, 2 cyl, 2 stroke, low rpm at WOT problems.

Try a different prop. My 11p wouldn't let me rev over 4200 due to what seemed like minor damage. A new one upped it to 5800.

 

[Suctoes]

Update...................

Update...................

Added Seafoam fuel treatment and changed plugs form champion to NGK. Checked prop, no damage. (Thanks for the reply jeep man.)

Took it out tonight and got to 3800 RPM. GPS said we toped out at a wopping 12 MPH (feels faster)! Anyway, I checked the primer bulb it was hard, tried choking at WOT and engine sputters and tries to die like it should from being flooded. Anything else I can try? Mabey drop to a 11 pitch prop? I don't know. Need more help please.....

 

[Suctoes]

Re: 2000 Mercury 40ELPTO, 2 cyl, 2 stroke, low rpm at WOT problems.

Anyone?

 

[Suctoes]

Re: 2000 Mercury 40ELPTO, 2 cyl, 2 stroke, low rpm at WOT problems.

my boat has a doel-fin hydrafoil on it. should I remove it and see if it helps?