6hp heavy load - prop assistance needed

[crxess]

Already working on a weird low rpm issue(1800 max @ WOT)

Boat - Bass Tender 10.2
Max rated hp - 7hp
73 Evinrude 6HP
Near Max load most trips out(450 or so)
present prop - oem 8.25x7.5
Boat is a trihedral(?) hull - non planing Hull design

Currently boat will only run about 2.5 mph - attitude level.
When alone, total weight around 365 Total(boat included) still under 4 mph. Slight bow up attitude. (6")

Found an 8.25 x 5 3 blade rated for heavy loads is available.
Should I give this a try?
Would it help with the RPM issue at all?

Any other recommendations?

 

[steelespike]

Re: 6hp heavy load - prop assistance needed

what is a bass tender 10.2?
I suspect your motor is running on one cylinder.Pull and ground one plug wire at a time and see if it will run or pull the plugs and look at them I think you will find one very wet possibly fouled.
You might also check that the stator is rotating as the throttle is advanced.
and that the throttle plate in the carb is opening all the way.

 

[crxess]

Re: 6hp heavy load - prop assistance needed

Bass tender 10.2 is a 10 plastic double hulled semi-flat bottom boat. Looks like a small tri-hull.

No on the engine issue. We are well beyond all the basic ideas. Both Cylinders firing Tested at full throttle under load. Fuel pump working good. Carb gone over 3 times with new kit. Spotless. Points coils all in good shape. compression 60/60

 

[steelespike]

Re: 6hp heavy load - prop assistance needed

Yes the 5" will give a signifigant improvement in rpm.Throw out the usual
200 rpm per inch on a small motor. It will gain a chunk more.I don't know if it will gain Close to 3000 rpm but what ever will sure help.A non planing hull
be happy with anything over 6 mph. I'd be interested to see the results.
It may run almost as fast at 1/2 throttle as full.

 

[crxess]

Re: 6hp heavy load - prop assistance needed

Thank you, that is what I was hoping to hear.
Even 6 mph would get me where I want to go. All my newly discovered fishing holes are 3-3.5 miles from the nearest ramps. 1 hour ride isn't bad but 2.5 is a lousy start to a fishing trip.

Found throttle cam wear, follower grooved and a possibly oversized High speed orifice in the carb. .052 instead of .044

Combined, these may be keeping the motor on the edge of flooding and killing power. Repaired Cam and follower and will try a pinch test this weekend.