02 DF140 Can get 5000rpm not 6200rpm?

[paulrevere]

Morning all,,,
i HAVE A DF140 02 MODEL w/700hrs, and runs great except,,,
At WOT i only hit 5200-ish rpms and i know I can easily hit the 6000 previously!
So, changed all fuel filters except "high pressure" which is next.
Would a full tank, i have a 60gal, hold it below the 6k w the added weight?
I changed absolutely nothing, same prop as previous ect....
and yes the throttle and shifter cable still move perfect, but maybe stretched?
ugh, any thoughts anyone?
Thanks and so far its behaved great..
P.

[paulrevere]

Found it!!!

After,, new high fuel filter, low fuel filter, primer ball, spark plugs, and removal and professional cleaning of fuel injectors..
The issue was....
I opened and removed the air box that connects to the throttle.
the throttle throat right in front of the throttle butterfly has a large screen, Its was 90% full with a mouse house that when the outboard would run would pull it against and block the incoming air for the outboard! Hence I couldn't get to the top rpm range and about to blow up the boat.
The mice also left about a 20oz cup full of nuts and bedding in the bottom of the air housing box,, this was easy to miss as the box is very secure and doesn't rattle and the manual doesn't show a screen on the throttle inlet!
so anyone with an 02,,, beware and check every few years for blockage, plus a good shot of carb cleaner to bring shiny didn't hurt.
P.

[Greg Moore]

Imagine the damage if that screen weren't there! Ingesting all that crap would spell death for the pistons/rods for sure..

[Glasspro]

Morning all,,,
i HAVE A DF140 02 MODEL w/700hrs, and runs great except,,,
At WOT i only hit 5200-ish rpms and i know I can easily hit the 6000 previously!
So, changed all fuel filters except "high pressure" which is next.
Would a full tank, i have a 60gal, hold it below the 6k w the added weight?
I changed absolutely nothing, same prop as previous ect....
and yes the throttle and shifter cable still move perfect, but maybe stretched?
ugh, any thoughts anyone?
Thanks and so far its behaved great..
P.

I have a similar problem like yours but my DF140 only does 3500rpm at WOT then it starts to govern. Any rpm under that the motor runs fine. Previous owner said he got some error codes but is not sure if they are old or new codes. I’ll post a pic of the codes detected. Would any one have any pointer or solution on this matter thank you

[Moonlighter]

Sounds typical of a neutral throttle switch failure.

The engine’s ecu is not getting a signal from the switch to tell it is in gear, so it limits revs to about 3500rpm by cutting spark, reducing advance and restricting fuel supply.

Suggest you check the switch and probably replace it - the the neutral throttle switch is on the gear linkages on the engine. No hard or expensive to do.

[Glasspro]

Moonlighter thank you for the reply, do you think i could bypass the neutral switch temporary with CAUTION and try to see if i can get a higher rpm? just to insure it is the neutral switch that is causing this problem.
thanks,

[Moonlighter]

A physical check of the switch is possible to show that its broken where it attaches to the linkages.

I dont know if you can bypass it safely or not.

Check this forum’s parts purchase section you will see its not expensive.

[Glasspro]

Did a check on the nuetral switch and could not find it to be faulty. I forgot to mention that when it hits 3500rpm i can hear the motor surge or govern which i assume its not a rev limiter

[Moonlighter]

Did a check on the nuetral switch and could not find it to be faulty. I forgot to mention that when it hits 3500rpm i can hear the motor surge or govern which i assume its not a rev limiter

That is exactly what the rev limiter makes the engine do. Cuts spark, reduces fuel. If you rev it in neutral it will do the same thing.

So how did you test the NTS? A physical inspection is only one check, its a micro switch so the electrical signal changes when its open or closed.

[tsturm]

I have a similar problem like yours but my DF140 only does 3500rpm at WOT then it starts to govern. Any rpm under that the motor runs fine. Previous owner said he got some error codes but is not sure if they are old or new codes. I’ll post a pic of the codes detected. Would any one have any pointer or solution on this matter thank you

Spun prop hub.

[Glasspro]

I found a cut in my fuel line on the low pressure side inlet to the low fuel filter. the way I found it was while I was pumping the primer bulb and I seen fuel leaking out of the hole/cut. also hooked up a computer to the motor and didn't find any current error codes. ill find out if this fixed the problem as soon I can drop the boat in the water for testing. will post after results
By any chance do you think this could be the culprit to my outboard problem?

[Moonlighter]

Yes, could have been sucking air at higher rpm’s.

well spotted!

Let us know how the water test goes.