2012 200 Pro XS still pulling back at higher RPM’s

[Judson1]

2012 Pro XS
S/N 1B965041

Posting again only because my last post I no longer see on here. So it’s been a few months. And I have taken the boat to a mechanic and a dealership. Both had been given very detailed info on what the engine is doing. So I am about $800 in so far. Plus several parts such as fuel line, primer bulb, plugs, fuel filter. Other than this one issue the engine seems to run great. Using the Merc monitor, I can hold the RPM’s with the Hotfoot within 10-20 rpms at midrange speeds. So for example 3650/3660. But opening it up, I can actually feel (and see) the rpms pulling back as much as 200 rpms. And that’s with the pedal to the floor. So if I can hold the pedal halfway down and stay within 10-20 rpms. Floored it should be no worse. But it may run 5350 for 5 seconds. Then pull back to 5150.
I have even noticed it occasionally at slightly slower speeds. Maybe around 4900/5000.
The dealership lake tested it. Reported it “running strong at 5400 with no fluctuating of rpms”. They did remove an aftermarket fuel filter the previous owner had installed and I didn’t know was a no-no. Plus the mechanic and dealership said no codes of any importance.
So now I am just trying to decide what to do next. I don’t run WOT very much. And I use 87 Conventional gas with the Quikleen/care cocktail. I will say the guy I bought it from (individual dealer) put a group 24 cranker in it. Noticing how weak the engine sounded while starting, I replaced with a group 31 that may not satisfy the minimum CCA for Optimax. The Group 24 had 1000CCA. But neither have sounded like they can turn the motor over very well. That couldn’t be it could it??
I mentioned I bought from a dealer. The boat was a repo. But it appears to be in good shape. The only problem is I can’t ask the last guy who owned it why he was content running 5380 WOT? Why the engine won’t spin the 25 Tempest any higher than that? “Most” guys with this boat/engine run a 24 or 25 pitch prop. I’m so far from 5750 I might have to drop to a 23. But I think prop swapping is secondary right now. I can run 65 which is 3-6mph slower than most others. Just really trying to do the right thing here. Any advice appreciated!
Also. The dealer I bought from did a compression test and all 6 were close but around 100-105.
Lincolnton Marine 3 months later had all 6 around 85-90. Isnt that pretty low? Or so long as they are all close it’s ok?

[SilverFox579]

You can locate your previous posts, or threads, by clicking on your username and bringing up your profile, on upper left you'll see two options, "Find latest posts" and "Find latest started threads".

This was your prior thread on this issue - 2012 200 Pro XS: How much RPM variation is expected at WOT?

[JOE54]

needs fuel and or air psi drop test done when problem is ocurring

[EuropeanAM]

^^^^^ +1

Also recommend monitoring LOW pressure fuel pressure AND HIGH pressure fuel pressure when this is occurring. Strap gauge set to front of engine and have someone take a video of the engine and gauges while you are driving the boat to replicate the problem.

Fluctuations in pressure (especially which one fluctuates first) can narrow down the field of causes.

[Judson1]

Thanks for the info!

[Judson1]

I would like to try and get this problem solved this summer. Looking at BBC everyday I have learned more and more (this place is great). I am going to inspect the battery/power side of this. I will check the cables/connections today. While I have a brand new Interstate 27size cranker, it is NOT on the list. This battery is 800CCA/1000CA. Only recently I found out the Interstate batteries ON the list aren’t under their marine tab. It’s under Commercial vehicles/industrial equipment. So now I can tell the manager where it is so he can finally sell me the correct one.

I put an external charger on my cranking battery prior to my last trip. Mainly because I get green lights on my onboard charger way sooner than I expect. The trim sounded more powerful. Not that it was weak before I could just hear a difference. But cranking the engine it still sounds weak. Especially the first crank of the morning. One thing I did notice is that the Oil “beep” as you turn the key sounded off every time during the fishing trip. That had been a problem recently. And I do occasionally get the “low voltage” message on my depth finder when cranking during the day. Even though I have that threshold set at 9.6 volts. But the display reads well over 12 while fishing. And 14.2 ish while running. I run two 9-inch graphs. So not a lot by today’s standards.
I just put a meter on it after disconnecting the onboard charger this morning. 13.33 Volts. Based on what I have read, this side of the system is showing some red flags correct?

Now to the engine itself. I could take it back to the last marine shop. But I think whomever I take it to should be asked first if they have the ability/desire to do the lake test AND be able to monitor the fuel/air pressures while running. I don’t want to pay again for a repair attempt that doesn’t include actually witnessing the problem. I will even take a day off work to assist if needed. Based on what some of you have said that test is a must.

Don, you are 2.5 hours away. But you fixed the problem on my previous boat after this same local marine dealer, and another, said they had it fixed. It was a very odd problem but only you found it. It doesn’t appear you are close to a lake. And I can imagine you are so busy you don’t have the time for lake testing. But I wouldn’t hesitate to bring it up to get that kind of service again. My plan is that locally I can get the problem fixed and then I can have the injectors sent up later for cleaning (275 hours). But I must find someone that will do the lake test with gauges. Also I have read others on here with similar problems rebuilt their Fuel Pulse Pump. Should I try that?

So with all that being said. Any advice on what you would focus on first? Anything you would do differently? I do want to point out this problem is sporadic. At times it’s not an issue. But most of the time it is. But something isn’t right. The prop/rpm output doesn’t compare with other like models. The drop in rpms can be felt. It’s just a matter of getting a tech around the problem when it’s occurring. I really appreciate the input you guys give every day to help others.

[lpugh]

needs fuel and or air psi drop test done when problem is ocurring as Joe stated above

[JOE54]

+1^^^^^^^

[Judson1]

Update: Got the call the injectors are back and boat is ready. Although I still wonder how they could diagnose dirty injectors as the problem. But if it was the problem pleasant surprise. Anyways while removing them to send off they said the oil pump assembly was “leaking profusely”. That one ruined my weekend but I told them go ahead and fix.
So on the call today he said while lake testing this morning the tech noticed a water leak in the cowling. And he recommends them removing the powerhead and replacing the gasket. As of right now I told him no. And I will come and pick up. Should I ask them if they ran it on muffs and checked for the leak? My analog speedometer doesn’t work either so I didn’t want to just say yes to another $500.
Im sure they are legit it’s just the way these other problems are popping up that’s got me leery.

2012 Pro XS- 260 hrs
S/N 1B965041

[castforcash]

If I were only 2.5 hours from Don, he would be the only person to ever touch my motor.

[clayc]

If I were only 2.5 hours from Don, he would be the only person to ever touch my motor.

AGREED.

[Judson1]

AGREED.

He has on my other boat. I love Dons work. But everyone was saying lake test and I looked at his shop and it wasn’t near any lakes. And I know he is super busy. I even asked him in this thread about bringing it up for a lake test but I guess he didn’t read it.

[Savage]

Powerhead gasket MUST be replaced, no if and or buts about it....gotta get changed.

[Judson1]

Powerhead gasket MUST be replaced, no if and or buts about it....gotta get changed.

Its being done. Thanks Savage.

[JOE54]

do tuner too,do both or dont do it at all, with updated hi perf gaskets

[Judson1]

do tuner too,do both or dont do it at all, with updated hi perf gaskets

Ok so I was unaware of that. They are having to order the other gasket so I will call them first thing and ask them to include the “tuner gasket”? Anything else? I’m already in about $2700 so what’s a little more while the powerhead is off.

Thank You Joe54.

[EuropeanAM]

He has on my other boat. I love Dons work. But everyone was saying lake test and I looked at his shop and it wasn’t near any lakes. And I know he is super busy. I even asked him in this thread about bringing it up for a lake test but I guess he didn’t read it.

Don't spend much time at the lake these days... very seldom that I need to.

That being said, been quite busy with my Dad, who lost his battle with Cancer on the 15th. Going to be out until this Friday.

[apdriver]

Don't spend much time at the lake these days... very seldom that I need to.

That being said, been quite busy with my Dad, who lost his battle with Cancer on the 15th. Going to be out until this Friday.

sorry to hear that, Don. Prayers for your family.

[castforcash]

Don't spend much time at the lake these days... very seldom that I need to.

That being said, been quite busy with my Dad, who lost his battle with Cancer on the 15th. Going to be out until this Friday.

Sorry to hear about your Dad, sincere condolences to you and your family.

[flinko]

sincere condolences to you and your family