Merc. 01 XR6 150 - MPH Decrease

[jgevedon]

Guys,
I have a 01 Mercury XR6 150 that I have had since new and it has been a great motor. This year I've started noticing a drop in mph and it now stands at a loss of 7mph this season. Compression check was great, no plug problems. Motor has never been overheated as well. Any ideas?

 

[j_martin]

Re: Merc. 01 XR6 150 - MPH Decrease

Boat's getting wet. Transom, floors.
I'm assuming the propeller is in top shape, not "ding'd up"

been there, done that

John

EDIT, I have no idea how this double post happened. I tried to post, got a server busy message, came back 4 minutes later and retyped the message and posted it.

 

[j_martin]

Re: Merc. 01 XR6 150 - MPH Decrease

Boat's getting wet. Transom, floors.
Driver/rider getting fat.
I'm assuming the propeller is in top shape, not "ding'd up"

been there, done that (on both counts)

John

 

[jgevedon]

Re: Merc. 01 XR6 150 - MPH Decrease

Actually I was just as fat beforehand so I gotta throw that out. Ha. On the boat wet issue, this boat stays covered year round and it doesn't leak at all that I'm aware. Prop is in great shape although I did replace the hub assembly this year.

 

[j_martin]

Re: Merc. 01 XR6 150 - MPH Decrease

Actually I was just as fat beforehand so I gotta throw that out. Ha. On the boat wet issue, this boat stays covered year round and it doesn't leak at all that I'm aware. Prop is in great shape although I did replace the hub assembly this year.

With something hard, but not brutal, tap on the transom in different places. If you get a solid sound all over, yer probably good. If you get a hollow sound, (likely near the top, or near a lower engine mounting bolt.) it could look like this.

On this boat, the upholstery is 20 years old and looks almost new.

John

 

[j_martin]

Re: Merc. 01 XR6 150 - MPH Decrease

Have someone (agile and tied off) pump the primer bulb at wot, and see if it picks up. If you're leaning out enough to slow down at WOT, yer looking for a meltdown. Usually they fall right off, but they could linger like that.

On the wet transom, mine allowed the engine to sag deeper, greatly affecting performance. When I stopped, everything sprang back into shape, and it went unnoticed till it got to the worm bedding stage.

With the transom and floors repaired, it's like a new boat. Very fun to drive.

John