2012 verado 300 WOT issues

[4426]

So we have a fairly custom 31’ aluminum express boat with twin 2012 Mercury verado 300s. We rigged the boat with those motors about 4 years/600 hours ago now but this whole time the port engine has always had a lower WOT(5850rpm vs 6150rpm on starboard). One is standard rotation one is counter. They do have 2150 or so hours on them. I’m just curious what would be causing the one motor to have a lower WOT?? We just went through and did fuel filters, plugs, coils, and oil changes so I’d think we’d have a little jump start on trouble shooting if we looked at this now rather than in the future. We have a vesselview screen with no active codes, that is where we are viewing the rpm data, and the controls are fly by wire/digital.

Edited July 11, 2023 by 4426

[Bozeman Bob]

I would do a compression test on both motors and compare numbers . Then I would try swapping props . I would verify the tachs with a tachometer as well . Next make sure your throttle cable is moving the motor lever to the end . Other than that I might post this question in Iboats or The Hull Truth as there are more outboard motor people there vs this site . 

[Shakemsam]

Has this always been the case? I am not at all familiar with counter rotating props and how this would work....If possible, I would compare both engines rpm,s running separately.  Perhaps the starboard side is over revving a bit due to lack of water. I don't know..just a guess..

 

[4426]

48 minutes ago, Shakemsam said:

Has this always been the case? I am not at all familiar with counter rotating props and how this would work....If possible, I would compare both engines rpm,s running separately.  Perhaps the starboard side is over revving a bit due to lack of water. I don't know..just a guess..

 

I rephrased my post a little, one is standard one is counter rotating. And unfortunately cannot plane on one engine so cannot compare one at a time

[4426]

58 minutes ago, Bozeman Bob said:

I would do a compression test on both motors and compare numbers . Then I would try swapping props . I would verify the tachs with a tachometer as well . Next make sure your throttle cable is moving the motor lever to the end . Other than that I might post this question in Iboats or The Hull Truth as there are more outboard motor people there vs this site . 

We did a compression test last year when we blew a lower unit just to check cannot remember the exact numbers offhand but everything seemed well within spec on engines. There isn’t a cable it’s digital controls. The tachs are on our mercury vessel view screen so I’m not sure why that would be inaccurate either 

[Bozeman Bob]

300 RPMs is pretty close , switching the props is all I can think of .None  of the 4 boats that I have owned with dual engines had the same top RPMs .Always off a couple hundred RPMs. That's all I got . 

[Terp]

It is very possible that the ECM's are different and each motor has a different rev limiter.