2016 DF20 WOT Issue

[ECU1984]

2016 DF20 manual start
cranks on the first pull every time, idles and runs out good.........until
once warm, at 100% WOT it starts to run crappy but you can back off the throttle just a tad to about 90-95% wot and smooth as silk.
I don't think its a fuel issue or it would have same issue at the 95% throttle
I am leaning toward throttle position sensor, thoughts?
Paging Red Lowery

[Moonlighter]

Sounds like it may be hitting the rev limiter? Although that is usually accompanied by an alarm?

Have you got a tacho so you can determine rpm at WOT?

[ECU1984]

Sounds like it may be hitting the rev limiter? Although that is usually accompanied by an alarm?

Have you got a tacho so you can determine rpm at WOT?

Good point, no tach, the motor is on a small 15' Gheenoe
I may buy one of those small mini-tachs and check the rpms.
If it is hitting the rev-limiter, what is the fix? changing prop?
Thanks

[Moonlighter]

If its hitting the rev limiter, then there are choices …..

If you rarely run much heavier, then yes, a prop with more pitch will reduce WOT rpm and get you a bit more mid range and top end speed.

As a rough rule of thumb if you stay with the same make/model prop, every 1” pitch change = about 200rpm.

Usually the rev limiter cuts in about 200rpm above the nominated red line of the engine, eg if the max rom is 6000 then rev limit cuts in about 6200 or a bit more. So if its easily hitting the limiter you could go with 2” extra pitch and still be close to max rpm at WOT.

But if you sometimes run a lot heavier and need the extra performance, you might decide to leave it and just use less throttle when running light so you stay below the rev limiter range.

I agree its a good idea to get some kind of tacho so you have a better idea of the revs you are achieving.

If you have a friendly Suzuki dealer they will be able to hook the engine up to the SDS software and it will show them if its been over-revved and how many times.

Its all recorded in the ecu so “big brother is watching”.

[ECU1984]

If its hitting the rev limiter, then there are choices …..

If you rarely run much heavier, then yes, a prop with more pitch will reduce WOT rpm and get you a bit more mid range and top end speed.

As a rough rule of thumb if you stay with the same make/model prop, every 1” pitch change = about 200rpm.

Usually the rev limiter cuts in about 200rpm above the nominated red line of the engine, eg if the max rom is 6000 then rev limit cuts in about 6200 or a bit more. So if its easily hitting the limiter you could go with 2” extra pitch and still be close to max rpm at WOT.

But if you sometimes run a lot heavier and need the extra performance, you might decide to leave it and just use less throttle when running light so you stay below the rev limiter range.

I agree its a good idea to get some kind of tacho so you have a better idea of the revs you are achieving.

If you have a friendly Suzuki dealer they will be able to hook the engine up to the SDS software and it will show them if its been over-revved and how many times.

Its all recorded in the ecu so “big brother is watching”.

Thank you!