New Verado 250XL - loss of power

[widnert]

Created new post to separate my motor from the other one started by JAZII. I'm having a similar issue to his during the break-in process.

New Ranger 2080MS and new Verado 250XL finally delivered to me Oct. 15 (after all the covid nonsense and a 20 week delivery cycle). After initial wiring issue from the factory (NEMA network) the dealer sorted out last fall, had only the analog RPM gauge to deal with - not consistently reading correctly from motor output. Didn't adversely impact operation while I was putting hours on the engine for break-in last fall and while I was learning about the new boat/motor.


Dropped off at dealer at end of January to fit in-between other work until our weather improved. The RPM gauge was exchanged for a new one from Ranger. Then, ECM on motor was swapped with a new one sent from Mercury, didn't fix it either so the original was swapped back in. Tech tried multiple things to correct RPM gauge behavior over the next few weeks without success. Tech was waiting for further guidance from Mercury support. Weather got good last weekend so grabbed it and got on the water to finish the break-in (was only at 6.3hrs on the clock when water froze last fall). Last November while using Lowrance and Vessel View, was regularly hitting 5600 rpm and 50mph during the short bursts of WOT (manual says motor should be between 5200-6000rpm @WOT). Pretty decent at our altitude - approx. 3200ft ASL on the lake I was using. Now, after only sitting over the winter, it is barely hitting 5000 rpm and 40 mph at WOT on Saturday. Same load as last fall, good fuel, engine sounds fine, no hesitantency out of the hole or anything. Am now right at 9hrs on the clock. Just seems to have lost 600 rpm and 10mph at WOT compared to my other runs last fall. Dealer has it again to continue sorting out the RPM gauge issue but, Tech was scratching his head over this change in behavior at WOT.


From the other thread regarding the ProXS 250 (very similar motor), I read that the strainers might be a cause and I'll mention that to the Tech. I also saw something mentioned about the coils. I'll suggest those be tested as well. I'm still learning about this motor and picking the Tech's brain as much as I can when talking to him so I'm researching those suggestions a bit more myself.

Any thoughts on other possible causes on this one? Thanks!

Mercury 250 Verado XL - SN:2B773957

[EuropeanAM]

Tommy- perhaps one of the best tests that can be done is for the tech to get it out on the water with you and:

1. Perform a RECORDING of the engine with the G3 Diagnostic System, which can then be watched over and over to monitor various items.

2. Perform a Cylinder Misfire Test at higher RPM's and record the RPM drop for each cylinder. If there is a problem with a plug wire, spark plug, or coil- this is perhaps the BEST method of narrowing the problem down to one or two cylinders (or it may determine that the problem is more GLOBAL in that all cylinders are producing the same amount of power).

3. Printouts of the RUN HISTORY and FREEZE FRAME History.

[widnert]

Thank you sir! I have already been chatting with him today. He's working on the Tach problem at the moment. I pointed him toward the FAQ thread regarding that. Hopefully, that resolves this problem. Then, he plans to move on to the engine.

[widnert]

Erratic Tach issue seems to be solved. For the Verado 250XL, the harness required a Grey wire to be de-pinned for things to work correctly.

WOT RPM issue is potentially solved. Tech checked the engine codes with the Mercury software and said there were a bunch there that seemed to be meaningless. After checking them all and finding no issues he cleared them all. Engine seems to perform fine at the shop. States he may have had the key on when he swapped the ECM while troubleshooting the Tach issue and theorizes this triggered all the codes and caused a sort of protective mode. He is testing things further today and will take it to the lake and run it to verify.

[EuropeanAM]

Widnert- do you happen to know if this was done in the Analog Instrument harness at the engine, or in the 14-pin harness?

[widnert]

The Tech did not pass along that info. He began with the Green wire note from the Memo mentioned before and states he couldn't locate a Green wire in the harness he was into. Then, through researching, he stated that the RPMs (unsure if digital or analog here) typically follow a Grey wire out of the harness he was looking at and that wire looked to be unused on the other side of the connector (?). He said tried de-pinning that one to get it away from the others and it appears to have resolved the issue. I'll have to ask him for more specifics later this week when I pick up the boat again. The problem was readily reproducible thus, if he tested and it was gone, he would know. The Lowrance at the helm with Vessel View was always accurate and provides a good cross-check to the analog gauge.

[EuropeanAM]

Thanks. This would be a good topic to keep in the FAQ Section (with documented resolution).

[widnert]

Confirming the de-pinning of the Grey wire was not at the j-box. Tech said it was at the harness at the engine. I can confirm after running it yesterday that the erratic tach issue is resolved.

Now, just have to finish troubleshooting the loss of top-end rpm. Tech cleared all the codes last week but, didn't have time to take it out to run it as a test. I tried yesterday and the problem still exists. Top rpm observed over the course of the day at WOT was 5100. Engine sounded perfect, no hesitation and hole shot was great still. Just not getting that top-end we had last fall before storing for the winter. I'll be scheduling a day this coming week to get the tech and take him and his computer to the water with the boat to perform a few runs with him.

More news as we learn more.

[widnert]

Met with the Tech at my dealer yesterday and took him, his computer and the boat/motor to the water to figure out the low rpm issue. Dropped it in and let the Tech drive. First run was perfect - rpms got right up to 5700. This was on the Ranger tach that was newly fixed. We stopped and turned on the Lowrance with Mercury Vessel View. This was the unit I was getting all my previous readings from. Unit turned on and Vessel View wanted to be setup for the first time. Now - this was different..... I was using this unit to watch rpms and verify the Ranger tach fix while on the water last Saturday. I know for a fact Vessel View was working just fine. I was watching it almost the whole day.

Well, Tech went through setup and got the Vessel View screen up. We took off on another run and motor performed flawlessly. I saw 5760 rpms at WOT with the Tech driving. I'm just shaking my head at this point. Conditions on this day were very similar to last Saturday when the max I could get was 5170 - no matter where I trimmed the motor to. Darn thing was running like a top and no issues. We made several more runs without any issues. Took the boat back to the launch and loaded it up and went back to the shop. Talked the issue over with everyone there and everyone was just scratching their heads.

My plan is to take it out again when the weather comes back together and run it again. Questioning my ability to drive the boat after this adventure. Anyway, we'll see if the issue comes back. I will report back if it does.

[satbeachbill]

Happens to me when I go to the doctor! Frustating.

[EuropeanAM]

Tommy- can you think of anything (however minimal) that might be different in the boat loading, fuel level, battery condition, amount of gear, etc? If not, you may just need to monitor and see if the symptoms can be repeated.

Did you happen to take the helm while the tech was on board and confirm that it would reach those RPM's for you? That's one easy way to rule out "whose backside" is in the seat, driving technique, etc.

[widnert]

The boat loading was very similar to previous times out. Full or nearly full fuel tank (started runs with Tech and fuel gauge read 3/4 tank). Only 2 people on board - me & Tech (previously, was me and wife and two 60lb dogs - each time). Other equipment on board was minimal and shouldn't matter. I've thought this through myself after being out with the Tech, trying to figure out what was different. I've come up with nothing. I was really starting to think it was me but, I've had it up to 5640rpms on at least 4 different outings last fall, just after taking delivery of the boat and before the water froze, working on the break-in hours. But, it "could" be me and I just get things trimmed correctly.

Batteries were fully charged - I had them plugged in at home before we went out each time. Only real difference was the temperature was much colder this last time with the Tech than my previous runs - both last fall and this year. It was overcast, snow flurries and 38 degrees with the Tech. On my other outings, the lowest temps might have been in the upper 40s to low 50s and partly cloudy to full sun on each outing.

I know I can get it up to the proper rpm range - or at least thought I knew I could. We're heading back back up to the lake Saturday, Lord willing, and we'll see how it behaves for us then. Supposed to be in the upper 60s and partly cloudy or full sun. Tech will have the phone with him so I can call with a report of what I am seeing on that outing.

I did not drive it while the Tech was with me. I should have but my mind didn't register that it would make any difference while we were discussing it. He even offered, I remember, but I waved it off thinking if I drove it or he drove it there should be no difference in motor performance. More news later...

[EuropeanAM]

[widnert]

Weather finally cooperating. Heading to the lake tomorrow.

[widnert]

Well - motor performed flawlessly for me this weekend. Peak rpms at WOT was 5610. Must have been operator error before or some gremlin that will come back again when I least expect it - SMH. Now picking up the research where I left off late last year, to consider changing prop to raise the WOT rpms up a couple of hundred to get closer to the max - or not.

One other thing, the Verado seems to have a trim-limiter to prevent the operator from trimming too hi up and allow cavitation while running but, not finding it in the documentation. Auto-trim was not enabled. This is a new motor to me with DTS so just wondering if someone else has noticed it? At idle speed, I can trim-up as high as I like to come into launch ramp. Just at speed, it will not rise above mid-level on the gauge.

[EuropeanAM]

There are both TRIM limits and TRAILER limits that are programmed into the PCM (with the G3 Diagnostic Tool). And of course- there's a maximum-allowed tolerance beyond which they cannot program.

Purpose is to prevent over-trimming while underway (which can be dangerous).