Evinrude/Johnson 50/35 Jet Owners, Typical RPMs @ WOT?

[Canadian Dave]

Hi Folks,

I just finished working through some mechanical problems with my new-to-me 1996 Evinrude 50/35 jet. I believe that I've identified and corrected all the issues. Today I took the boat down to the river and checked/reset the timing following a trigger coil repair (reglued). Because I've never owned this motor while it was performing at 100%, I don't know what to expect re: WOT RPMs. The motor starts and runs great, but peaks at 4950 RPM. I was expecting something in the 5500 to 5750 range, because that's what my experience with propped outboards tells me it should be. I've yet to confirm that the RPM gauge is accurate, but assume that it is.

The motor has a new stainless impeller and wear ring set to tight side of the specified clearance.

I'm wondering if there are other Evinrude 50/35 jet owners out there that could share what they typically see for RPM at WOT?

Thank you for your help, it's much appreciated!

Have a great day.

 

[BigTerp]

My 1994 Johnson 50/35 with stainless impeller and Carson reeds spins about 53-5400 at WOT. I keep mine shimmed pretty tightly as well. IIRC, manual for my motor says WOT range is 45-5500.

 

[stinkfoot]

I set my Merc 40/30 on the tight side a couple of months ago. So tight I wore a nice groove in the liner. That definintely affected my WOT rpms......

 

[Canadian Dave]

Thank you very much BigTerp, much appreciated. I guess it's time then to look for that missing 300-400 rpm. Now if I could just remember where I left it sitting!

 

[Canadian Dave]

Hi stinkfoot,

Just a word of caution. When setting your impeller to liner clearance to the tight side of the specified tolerance you first want to confirm that the pump's bearing assembly is in good condition and there is no deflection in the impeller. If you're running it on the tight side with deflection the impeller may be forced into your band new liner as the impeller spools up. Sadly this is from recent experience . I never had an issue when the motor would only run at 4500 rpm but once the trigger coil was repaired, and the motor was capable of spilling at 5000 rpm, there was contact . . . . solid contact. Arg!

 

[stinkfoot]

Hi stinkfoot,

Just a word of caution. When setting your impeller to liner clearance to the tight side of the specified tolerance you first want to confirm that the pump's bearing assembly is in good condition and there is no deflection in the impeller. If you're running it on the tight side with deflection the impeller may be forced into your band new liner as the impeller spools up. Sadly this is from recent experience . I never had an issue when the motor would only run at 4500 rpm but once the trigger coil was repaired, and the motor was capable of spilling at 5000 rpm, there was contact . . . . solid contact. Arg!

Haha thanks, Dave. It ran perfectly fine till I got carried away with a shim too far!

 

[Shinyboat]

I have the same issue. Did you ever find a way to get higher rpms?