F225 won't go over 4300 rpm

[Jcreasy225]

Runs fine under 4300 but shakes a little when throttle up to go over 4300 rpm. If I stop shut engine off turn batteries off then back on start engine runs fine , strange I'm thinking electrical, just had 100 hr service done,screens changed,mechanic said not showing any codes. Anyone else had this issue?

[boats.net]

Need to run fuel vacumn and pressure test to see if getting enough fuel.

[Jcreasy225]

Even though it doesnt do it after I reset the batteries after that it will run normal all day unless I shut off motor.

[boats.net]

Check battery cables and battery switch see if corroded.

[boaterholic]

any updates on this? may have similar problem, although the one engine that does this on a twin engine boat will shake a little bit regardless the cruise rpms, but smooth at idle. other engine smooth throughout rpm range.
thank you

[Sequoiha]

I had this same issue last week on a F225, ended up being the VST filter was stopped up, replaced the filter and the VST oring and she is good to go.. hope this helps

[boaterholic]

thanks, I plan on checking the vst filter, but in my case it's been doing it for about 150 hours on my starboard engine, and I did check and replaced the vst filter last summer and it still was and is shaking after that. And the vst I think had one speck of dirt on it about size of pin head but otherwise clean. And I ran it with a fuel pressure gauge and it is getting 40 - 42psi throughout the power range so I doubt the problem is fueling. I even had the injectors cleaned and still no change. While at cruise speed the shake almost resembles a 2 stroke outboard at idle in how it shakes a little from side to side.

[Bgilderman18]

Answer

The problem is fixed by replacing the shift position switch. Inexpensive fix and after having this problem for over a year it is finally fixed on my boat.

[boaterholic]

The problem is fixed by replacing the shift position switch. Inexpensive fix and after having this problem for over a year it is finally fixed on my boat.

what were your symptoms? Were you able to trouble shoot the switch while mounted? The reason I ask is with my engine running and cowling off I can play with the switches and with the upper of those two switches if I push the contact in it just slows down about 100-200 rpms, if I unplug it nothing happens. The lower switch, which I think is the one you changed, if I grab the whole shift mechanism and rotate it counter clockwise a little it makes the contact on the switch and it runs very rough and then smooths out again when I let it go to where it just has a little shake as before I started messing with the switch. If I unplug it nothing happens except at idle it speeds up about 200 rpm's, but interestingly when I plug it back in it wont slow back down again until I turn engine off then back on.

Thanks.

[rodbolt17]

its a switch.
its either on or off.
simple to test with a multimeter,even easier to watch on the laptop.
its also helpful to know why the switch's are there to start with.
the shift position switch(on or off) simply tells the ECU if the engine is in a gear or NOT.
if the ECU "sees" its in nuetral and the RPM's increase it will start the over rev function and limit RPM.
if it detects an in gear and a crank signal at the same time it may limit RPM again,depending on engine model.

the shift CUT switch,again on or off, detects the shift motion during a shift from any in gear TO nuetral and misfires the engine to unload the propshaft and allow the shift clutch to more easily disengage.
depending on model the RPM this function is ignored may vary.

the laptop will shift from on to off or off to on as you move the shift linkage, its very easy to see.
however if you dont know what and why the switch's are there your sunk.

[boaterholic]

Rodbolt,
from the description I gave of the operation of the switches on post above yours, does it sound like they are doing their job to you or not?

From your experience, does it sound possible that if the shift position switch is not working correctly, it could cause my outboard to shake a bit at cruise speeds? The engine runs all normal rpm's it is supposed to, all the way to 6000. It just shakes when it running. To compare the shakes, if you look at a two stroke at idle and think about how it shakes a bit side to side, that is kind of what my engine looks like underway at cruise. It did not always do this; it started about 250 hours ago. It's my right engine. Left engine is almost perfectly smooth.

If I need to look at this switch on laptop (YDS), where do I see its operation. I've only used YDS a few times so not intimately familiar with it.

Of the two switches in this area, the shift position switch is the upper one where the "shoe" connected to the shift cable slides, correct?

Thank you for help.