2012 200 Pro XS: How much RPM variation is expected at WOT?

[Judson1]

I am trying to figure out why my engine won’t even hit 5400. Don’t have the luxury to ask the previous owner if he just had it over propped. But the boat jumps out of the hole so I figured the prop should be giving me more rpms.
One thing I noticed on the Smartcraft gauge is while running 5350 or so it routinely pulls back around 200 rpms. So it’ll go back and forth between 5350 and 5150 for example. I can feel the boat pull back a bit.
So before I just slap a 24 pitch on there chasing the extra rpms I wanted to ask if there may be anything I should check? A mechanic checked for any codes and did a light service and says he didnt see anything. Someone mentioned a while back a Fuel Pulse Pump??
As preventative maintenance the plugs, compressor strainer, and fuel filters have been changed.
It’s a 2012 model with 250 hrs.
thanks
S/N 1B965041

[JOE54]

fuel psi test at 5350 when it pulls back, dont change that prop yet

[EuropeanAM]

+1

Also need to look for other basic problems, including Compression, Spark Test (inspect plugs and wires as well), belt and tensioner*, water spotting indicating water leaks inside the cowling, etc.

* Tensioner spring should hold at least 70 lbs/in torque (torque wrench set to 70 lbs/IN should click before tensioner arm contacts flywheel cover retainer/stand).

[Judson1]

+1

Also need to look for other basic problems, including Compression, Spark Test (inspect plugs and wires as well), belt and tensioner*, water spotting indicating water leaks inside the cowling, etc.

* Tensioner spring should hold at least 70 lbs/in torque (torque wrench set to 70 lbs/IN should click before tensioner arm contacts flywheel cover retainer/stand).

Thanks Joe and Don. Compression was checked upon purchase in October. I will work on getting the other items checked. Would dirty injectors possibly be a cause as well? 250 hrs on engine. I just know my previous engine ran great after your service a few years back. Again yesterday many times I witnessed the smartcraft fluctuating around 200 rpms at WOT. Except for that and sounding weak at first start, the engine seems to be running well.
S/N 1B965041

[EuropeanAM]

While injectors are a possibility, the other mentioned items definitely need to be ruled out FIRST.

[Judson1]

Ok so before I take it in one more question. Is this a problem that could lead to something bad? Or is like having the wrong prop in that you just live with reduced performance?
Noticed at mid range speeds yesterday the rpms fluctuate only 20-30 rpms. And that is with my foot not having the aid of something to press the pedal against.

[JOE54]

problem needs to be adressed

[EuropeanAM]

Ignoring engine problems and/or considerable changes in running condition or performance (and continuing to run the engine) could potentially result in further engine damage.

[Meadows]

I’m dealing with the exact same issue on the exact same motor, it’s been going on for awhile now. I’ve had spark plugs replaced, played with the PTP and prop, new battery, compression checked, etc.

Its currently in the shop and they’ve found a small leak in my oil pump, and I’m having them check my vapor separator tank, fuel lines, and alternator. If the culprit is found I’ll let you know.

[Judson1]

I’m dealing with the exact same issue on the exact same motor, it’s been going on for awhile now. I’ve had spark plugs replaced, played with the PTP and prop, new battery, compression checked, etc.

Its currently in the shop and they’ve found a small leak in my oil pump, and I’m having them check my vapor separator tank, fuel lines, and alternator. If the culprit is found I’ll let you know.

Now I haven’t driven mine since. But one of the things the tech found was an aftermarket inline fuel filter. I knew it was there and that it wasn’t in my previous boats. But didn’t take it out. He 7A05CB5E-70CC-4881-A621-C1DA8480E9B4.jpeg aid it was not supposed to be there and removed it. He reported slightly more
rpms than I did and said it wasn’t fluctuating with him. Other minor items are listed in picture.

[JOE54]

no telling how many blown powerheads are caused by that every year from lean conditions

[Judson1]

no telling how many blown powerheads are caused by that every year from lean conditions

Yeah now that I know I’ll be worried if damage may have already been done.��