Mercury 115 2+2 RPM issue

[RangerRic]

'97 Mercury 115 2+2. Whether I use
a Black Max 23 or 21 pitch prop - 1 or 2 people in boat - motor down or trimmed up -
WOT is always 4600 rpm. (or 4400-4500 trimmed down) Just seems like it 'hits the wall' at 4600 -
runs fairly well otherwise.

????

[JOE54]

ser num /check linkage adjustments

[RangerRic]

OG556945 - have an appointment with mechanic for Friday - will mention linkage issue to him.
Could a rev-limiter problem be the culprit?

Thanks ...

[06 SB]

The RPM limiter for the 2+2 is pretty much right at 5250 and feels like the motor is surging. 4600 is a ways off from that. I would suspect linkage too or if it feels like it is surging, it could be a bad tachometer.

[RangerRic]

Not really surging at 4600, just not going past. Put in a new tach and a new 21 pitch prop.
Boat ran great in Florida - this issue surfaced after I brought 'er to Minnesota.

[lpugh]

Not really surging at 4600, just not going past. Put in a new tach and a new 21 pitch prop.
Boat ran great in Florida - this issue surfaced after I brought 'er to Minnesota.

Elevation differance between locations?

[RangerRic]

Would be surprised if 600-1000ft difference in elevation would be that significant, but .....

[lpugh]

I would be to, but 1500 plus ft may cause it. I just noticed the move in location and thru that out there

[JOE54]

good tech will start with basics comp, spark , fuel, set up, linkage,

[RangerRic]

I asked about linkage and he said stuff already checked include carbs, fuel, lines, linkage, etc.
Setup not considered by him - probably because I told him it ran so well in Florida.

The mechanic did mention 'spark advance' as the next thing he was going to check.

Appreciate the responses - he is a guy who actually seems to listen to the customer.

[JOE54]

thats good,might check for something loose from road trip, report back

[RangerRic]

To me, had to be something that changed between Fl. and Mn. (will bring that up to him again)
and that it may not be something obvious (i.e. $$$$).

[RangerRic]

Update. Mechanic in a motorcycle accident, so he fell (sic) behind.
He has motor now, hoping to hear something soon.
(already started researching a repower, just in case ....)

[JOE54]

[RangerRic]

Well, mechanic spent approx. 8 hrs., multiple calls to Mercury and consultation with
other mechanics to no avail, so he and I gave up. Gave me $700 trade-in and
'ate' the labor above, on a new motor.

See Selecting a 115hp outboard in the General Bassboat Topics forum.
(http://www.bbcboards.net/showthread.php?t=918421&page=2)

Thanks for all the help here!!! - I kinda thought this is where I would end up, as
4 separate mechanics over two seasons ended up scratching their heads as well.