Merc 125 tune-up question

[wiggreb]

I have a Merc 125 saltwater. It has been used pretty lightly for 3 seasons. I want to take it in for maintainence, but I don't want to tell them to "tune it up" for fear of being taken for a ride. So what needs to be done at this point, as far as routine maintainence?
(The lower unit oil has been changed on schedule)

 

[Don S]

Re: Merc 125 tune-up question

What year? 4 or 2 Stroke? Carbed or EFI?

 

[wiggreb]

Re: Merc 125 tune-up question

2004 Merc 125 saltwater; 2-stroke.
Carbed or EFI? I don't know. Hey, it's my first boat. I think it's carbed though.

 

[Don S]

Re: Merc 125 tune-up question

Well, it makes a big difference, do you have a Merc SN handy?

 

[wiggreb]

Re: Merc 125 tune-up question

Yep, it's carbed.

 

[Don S]

Re: Merc 125 tune-up question

Basically, a compression check, new plugs, and running some powertuner thru the engine, new fuel filters should take care of the motor.
If you have any rough running or idle problems and/or the previous owner tinkered with the motor, a Sync and Link may be in order also. You would need an OEM service manual for any repairs should you decide to try doing it yourself.
Since it is 3 years old (an a salt water motor) a new impeller is recommended, along with greasing the splines on vertical shaft of the lower unit, and a gear lube change.
If you PM me with your email address, I have an owners manual for your engine in .pdf format I could send you. It's 607KB in size.

 

[wiggreb]

Re: Merc 125 tune-up question

Thanks for the info - a couple more questions if you don't mind

1. Most things I'll leave to the pros. To change plugs, is it as easy as taking the old ones out and putting in new ones? Do they have to be torqued?

2. What's powertuner? Is that something a rookie could do?

3. What's a link & sync? It idles pretty well, once warmed up a little.

4. Greasing the splines? Is there a grease fitting for that or do you have to open up the lower unit?

 

[Don S]

Re: Merc 125 tune-up question

With those questions, what you need is the OEM service manual. Then study what has to be done for each job so you know what is involved.
The Merc PN is 90-830234R04

The "Engine Tuner" comes in a spray can and is spayed into the carbs of a running engine to clean carbon off the rings. It's a Merc product and details are on the can.