2002 Mercury XR6 150 Not Reaching Speed.

[honnndaaa]

Hey everyone,

I have a 2002 tracker avalanche with a 2002 mercury xr6 150hp with a 23p laser prop. I am just not achieving the speed that this boat should be getting. Out of the box should be they tested at 63mph. I am only achieving 45mph gps loaded with 2 lighter guys. Tach shows 5200rpm max should be 56-58 from what ive read. I installed and inductive pickup tach to try and confirm but unfortunately only reads up to 5000 but seem to be pretty close to what tach reads up to that. I feel i have exhausted all the checks i feel are needed that i could find reading online, so hopefully I can get some input from the experts.

What I have done that check out good:

Compression is good 120ish all around
Replaced fuel filter
Checked fuel pressure
Link and sync
Checked timing(missing flywheel cover but followed manual measured and install and marker)
Ensure throttle is opening all the way
Checked to confirm proper lower unit(spinning flywheel and checking ratio to prop, i know not the best but if i had different gear i would assume holeshot would be way better)
Check plugs every so ofter dont seem to be lean but very oil saturated which Im told is normal.
Motor is in the proper mounting position(suggested position and measured myself for what should be optimal)

I am sure I am missing somethings I checked but this is what i can recall. I am a licensed automotive tech so doing all this is not an issue but outboard 2strokes are a bit of a different breed for me and not exactly sure what I should be looking for that may be out of place. Any suggestions are greatly appreciated and will redo any checks or adjustments suggested.

Thx,
Bobby

[FMP]

It's 35° / 40° C + with the humidity, that'll eat HP like night and day, even more noticeable if it is conservatively tuned rich and less ign provided everything working properly.

[honnndaaa]

It's 35° / 40° C + with the humidity, that'll eat HP like night and day

Hey thx for the reply but temperature has not been a contributing factor. This has been an issue since i got the boat last year and speeds are the same give or take hot or cold.

[FMP]

Pull the anchor in?

How oily ?


How heavy everything in?


Swap props?


Check coils and plug wires 100%

[honnndaaa]

Pull the anchor in?

How oily ?


How heavy everything in?


Swap props?


Check coils and plug wires 100%

I can take pics of old plugs this evening

2 guys and gear under 1000lbs(saturated foam causing extra weight is a possible concern but not sure if i would loose that much speed)

Havent tried a new prop but a 23p is what everyone is using on this setup and all achieving min 55mph

What checks should be done to the coils, i have check wires for proper resistance and check for good strong spark. Plugs are new every year gapped as per manual and correct pn

[KIRCHNER]

I BELIEVE all 150 had a 2-1 gear, so improving hole shot is not an option, 2-1 being the steepest ratio available. that 55mph mark may be a bogus #. sounds like you have a good running motor. try pulling off each plug wire at idle, see if all 6 are running. rpm drop should be equal, cyl to cyl. i ran your numbers thru prop slip chart, shows crazy slip %.

[FMP]

Was thinking it has a fail-safe for oiling if it gets blocked and just pours it heavy to save the day.

[tlwjkw]

still had plain 'ole oiler... it will be tha 1.87 gearcase.. offset?.. height?.. work on set up first.. that's an "electronic motor so ya limited with what ya can do.. make sure everything is doin' its part.. carbs can be rebuilt and fuel delivery can be checked/fixed if necessary.. 'lectronics can be checked.. if ya send me an email address, i'll send ya an oem manual in pdf for it.................

[KIRCHNER]

Somethings off, merc slip chart shows 50%! with the# hes giving. chart isaccurate. 26% w/ 1.87

[honnndaaa]

still had plain 'ole oiler... it will be tha 1.87 gearcase.. offset?.. height?.. work on set up first.. that's an "electronic motor so ya limited with what ya can do.. make sure everything is doin' its part.. carbs can be rebuilt and fuel delivery can be checked/fixed if necessary.. 'lectronics can be checked.. if ya send me an email address, i'll send ya an oem manual in pdf for it.................

It still has the oil injection. I think your correct on the gear being 1.87. motor is mounted in the second hole and i have measured and it is where it should be. Havent done anything to the carba because my thinking is itals running well and not showing and signs of leaning maybe rich if anything. Will pm you my email.

[tlwjkw]

It still has the oil injection. I think your correct on the gear being 1.87. motor is mounted in the second hole and i have measured and it is where it should be.

second hole?.. no jack plate?.. need measurement from prop shaft center line to pad for correct height..

[TNRoostertail]

We definitely need to know your prop to pad. Those little motors like to run up to 6k rpms. Your losing some speed not having it reach its peak imo.

[Whaaaaat]

Change gps settings from knots to mph?
Seen this and done it myself. What are you using to measure speed?

[FMP]

You sure it's the correct powerhead, just kidding.

[KIRCHNER]

HE did say its always ran the same since hes owned it! is it a 2stroke or 4? maybe its not a 150...