03 df140

[FLDXT08]

Seem to be hitting a rev limiter at 5700 rpm or so, not inside the range set by manual. No light or warning buzzer. RPMS drop to about 2700 and then start to pick up again if I don't come back on throttle. Not acting like a rev limiter hit as stated in the manual. Otherwise the motor is running flawless. Thinking a tach issue or ECM? Any help would be appreciated.

Excuse me - an 04 DF140

[noelm007]

I think you would know if you had a tach issure, going from 5,700 to 2,700 is pretty noticable, also doubt it has anything to do with the rev limiter, I reckon your first bet would be to take it to your dealer and get them to run the diagnostics on it, now you say it does not alarm or warning lights, so maybe nothing will show, but then, maybe it will, if you dont start with the easy stuff, you will end up spending a bucket load and be no better off. After the diagnostics are run, try a complete remote tank and hose with fresh fuel, remove the spark plugs and have a look at them, are they all the same? do you have an inline filter system? if so, check or replace it.

[FLDXT08]

Just replaced all the fuel filters and seperator, changed plugs, they were all the same. The more I read the more I think it might be a vent issue or one of the filters, I havent ran it WOT since the filter change. But it sound slike the motor is starving for fuel when it is requiring a large amount. Going to run it and see if it happens again, then start with the vent at the fuel tank if the problem persists. After that it will be at the dealer to check for codes. Noelm007, I sure do appreciate the response, I was sure looking for some advice.

[noelm007]

can you borrow/buy a complete small tank and hose? that will eliminate a whole host of potential problems in one go, and give you somewhere to look, to test the tank vent is pretty simple, just go for a run and remove the filler cap, this will vent the tank easy, but you may have a partially blocked pick up or something, that's why a remote tank is great test

[FLDXT08]

NoelM007, I am going to give it a whirl this weekend and see what happens. When I was experiencing the problem, the boat still has some old fuel in it. Since I ran all that out and serviced everything I have not had an oppurtunity to check. I will try that this weekend with the filler cap if I experience the problem and see what happens. I have heard everything from a tach issue, to ECM, to don't worry about it, to tank vent issues. I have eliminated any prop issues thanks to the guys at PowerTech, I am dead on for number at lower RPM range. The motor runs flawless all the way up to this RPM range when I was experiencing the problem, and I have run it since, just haven't pushed it up to the 5700rpm area. Again, I appreciate the advice!

[noelm007]

you need to do the very easy, cheap non invasive stuff first, no use doing brain surgery when all you needed was a haircut! plenty of people start pulling things to bits and buying all sort of parts in the "pray and hope" method, you need to be systematic and thorough with the simple things first.

[FLDXT08]

I will do that! I tend to lean towards the biggest, worst possibility first, that is usually where things go for me. I'm hoping just a fuel delivery problem. I will let you know how it worked out after testing. Again, thanks.

[FLDXT08]

Noelm, what do you think about a clog in teh VST screen causing this problem? Talked to another Zuke mechanic today and that is what he suggested. Said I had to remove the manifolds to get to it, not sure if that is brain surgery or not?

[noelm007]

yep, could be the cause BUT, do not start a scattergun approach by fixing 10 things then testing, do the SIMPLE things first and test, be methodical or you will end up in a mess and get nowhere. have you tested the motor since you changed the filter, fuel and plugs? if not, do it before moving on.

[FLDXT08]

10-4, will do it! Appreciate it!
One last thing since you are being so helpful, which I appreciate! Do you know if they have online manuals for this motor?