No top end

Rssuttle

Well-Known Member
Messages
49
Reaction score
22
2022 SXL 18 with 60 horse mercury. Engine rpms top out at 3600, with 12.5 MPH. Returned to dealer that suggested giving more trim. I tried trimming out but had the same result. It appears that there is no throttle response until the throttle is moved to about 1/2 of the total forward travel. Once that point is met there is acceleration until about the last 1/4 of forward travel. After that point there is no additional acceleration. In reverse same with about 1/2 required before any increase in rpms.

There is a about 70 hours on the boat now.

The dealer said if trimming out didn't get me there then they would replace the prop, but It seems to me the problem is in the throttle.

Any suggestions or thoughts are greatly appreciated.
Did you get this problem fixed
 

SLXJOE

Member
Messages
22
Reaction score
21
My dealer gave me a 13.8 X 11 prop to try. I now have done 2 complete runs calm lake, no wind, clean pontoons. In both cases the tach stops at 5200 rpm at 17 mph even though there is still forward throttle travel. Both are lower than I believe they should be. I still think I may have a throttle issue.
 

Rssuttle

Well-Known Member
Messages
49
Reaction score
22
My dealer gave me a 13.8 X 11 prop to try. I now have done 2 complete runs calm lake, no wind, clean pontoons. In both cases the tach stops at 5200 rpm at 17 mph even though there is still forward throttle travel. Both are lower than I believe they should be. I still think I may have a throttle issue.
What was on it first before putting 13.8x11
 

tinkertoy

Well-Known Member
Messages
61
Reaction score
69
I still think your pitch is too high. I've got a 13.5 x 12 on my 90 SHO and it's about right.
 
Last edited:

Rssuttle

Well-Known Member
Messages
49
Reaction score
22

Check this site. Put in your numbers as accurate as you can. You can do it as performance or weight or try it both ways. It might help
 

SLXJOE

Member
Messages
22
Reaction score
21
it recommends 13.4x15. Thats what I originally had. The new set up is closer. I think If I response from the throttle for the last inch of travel I would be right in the ball park around 5700 rpms at 20+ mph. I just dont know if you can adjust the throttle.
 

jcr159

Well-Known Member
Messages
111
Reaction score
80
Location
portage lakes, oh
it recommends 13.4x15. Thats what I originally had. The new set up is closer. I think If I response from the throttle for the last inch of travel I would be right in the ball park around 5700 rpms at 20+ mph. I just dont know if you can adjust the throttle.

Have you tried adjusting the throttle/shift lever? There should be instructions for your rigging that walk through how to set travel, drag, etc on the shift and throttle control at the helm. I’d review all that configuration to make sure you are really getting the right travel and verify with the motor shut off and cowl off that the full throttle is opening the throttle body fully.

At that point you can safely probably say that this is a prop issue…
 

SLXJOE

Member
Messages
22
Reaction score
21
I have searched the internet many times looking for instructions on adjusting the throttle/shift lever but haven't found anything on it.
 

1BadassMarine

New Member
Messages
2
Reaction score
2
2022 SXL 18 with 60 horse mercury. Engine rpms top out at 3600, with 12.5 MPH. Returned to dealer that suggested giving more trim. I tried trimming out but had the same result. It appears that there is no throttle response until the throttle is moved to about 1/2 of the total forward travel. Once that point is met there is acceleration until about the last 1/4 of forward travel. After that point there is no additional acceleration. In reverse same with about 1/2 required before any increase in rpms.

There is a about 70 hours on the boat now.

The dealer said if trimming out didn't get me there then they would replace the prop, but It seems to me the problem is in the throttle.

Any suggestions or thoughts are greatly appreciated.
I had an issue for almost (3) years. I tried (4) different props. New fuel filters all the way around. Looked at the injector output. New plugs, etc...I have a 90 hp Yamaha on mine. Bottom line; Yamaha had a foam piece that was not a filter. It was for sound. This piece of foam sat in front of the air intake and it came unglued and it was keeping my enigne from getting the proper air. Killed my RPM by 1200. I re-glued it and my performance came back! I ordered a new air intake since Yamaha had 3 revisions since mine came out. I thought they might have re-designed it. Nope. All they did was put (3) plastic wire ties on it... I waited 6 months for this new part...
 

PartyBarge

Well-Known Member
Messages
267
Reaction score
238
My dealer gave me a 13.8 X 11 prop to try. I now have done 2 complete runs calm lake, no wind, clean pontoons. In both cases the tach stops at 5200 rpm at 17 mph even though there is still forward throttle travel. Both are lower than I believe they should be. I still think I may have a throttle issue.
Maybe, but the performance increase is reasonable for moving from the 15p to a good 11p. Had doubts 60 HP would turn an 11p Nemesis to full RPM. IF the dealer has a 10p Nemesis grab it. Note that would be another ~9% drop in pitch and should put your RPM somewhere around 5700. If not check for a 10 or 11p Yamaha Talon. In any event there likely is only a little more speed to be had...

Worth noting that the "bigfoot" option has it's advantages, but they come with a bit more drag too.

P.S. Calculated slip for your current setup is a rather high 27%. That is not typical for a Nemesis. Pontoon weight or motor height may be issues, although actual prop RPM may be a little low for best hook up. Try less pitch.
 
Last edited:
Top