225 EFI Scheduled Maintenance????

I have a 1998 Mariner 3.0L 225 EFI. I have never done anything to it except yearly spark plugs, water pumps, lower unit lube, fuel water separators, etc.

Considering the motor is now going on 11 years old, are there any parts I should replace or maintenance I should perform? I do not mind spending money on parts as preventative maintenance if it will ensure no breakdowns on the water and proper performance. I am considering installing a new diaphram kit in the mechanical fuel pump (cheap insurance at less than $20) as I know they tend to lose their elasticity over time and are prone to pin holes.

Does anyone else have any suggestions? Should I change the fuel line in the splashwell? Thermostats? Poppet valve?

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by OverRHeads &raquo;</TD></TR><TR><TD CLASS="quote">I have a 1998 Mariner 3.0L 225 EFI. I have never done anything to it except yearly spark plugs, water pumps, lower unit lube, fuel water separators, etc.

Considering the motor is now going on 11 years old, are there any parts I should replace or maintenance I should perform? I do not mind spending money on parts as preventative maintenance if it will ensure no breakdowns on the water and proper performance. I am considering installing a new diaphram kit in the mechanical fuel pump (cheap insurance at less than $20) as I know they tend to lose their elasticity over time and are prone to pin holes.

Does anyone else have any suggestions? Should I change the fuel line in the splashwell? Thermostats? Poppet valve? </TD></TR></TABLE>

At this age: I'd recommend that you replace the pulse fuel pump diaphrams/check valves, and consider fuel lines and/or oil lines.

Visual inspection of every external comonent is a good place to start- many times, a "set of eyeballs" is the most valuable diagnostic tool! If something "appears" to be worn, address it now, rather than later.

Thermostats are a good investment- poppet valve is not very expensive, and would also not be a bad idea!

Inspection of the oil tank pickup for debris is also a good idea.

One of the best "band for the buck" items that I would recommend would be cleaning the fuel injectors. Many have seen excellent results from the services offered by Brucato.... http://www.bassboatcentral.com/smileys/wink.gif

Of everything involved- a leakdown test of the engine would be one of the most valuable pieces of information. This will give you an accurate measure of the "internal" health of the engine- and may, in some cases, allow you to realize that a "refresh" of the engine is in order (prior to any major damage). Of course, if leakdown results are good, you'll also have the peace of mind knowing that "tearing into the engine" is not necessary at this time!

You're on the right track- research has shown that in general, "every dollar you spend on properly done preventative maintenance will likely save you three dollars in future repairs". http://xs-s.com/zf/images/smile/emthup.gif

I brought the boat home and hooked it up to the muffs and it would not shift into gear. Instead it made a horrible grinding noise (clutch dog not grabbing). I pulled the cowl and checked the shift cable and it was out of adjustment. I adjusted per Mercury service manual and it locks into gear perfectly.

As I was solving that problem, I noticed that it was idling high which resulted in hard shifting. I will be completing some of the above mentioned preventative maintenance (spark plugs, lower unit lube, pulse fuel pump diaphrams, thermostats, poppit valve) this weekend. After I replace the fuel pump is there a way to adjust the idle down? It is currently idling at about 950-1000 rpm's and the manual and sticker on side of motor say it should be more like 650-750 rpm's. I checked the linkage and cam roller and they are going to WOT as well as returning to idle like they should. Also, it has been a dog out of the hole lately. Will the fuel pump and idle adjustment (if possible) help this?

Thanks!

Fuel pump and spark plugs MAY improve your holeshot- you'll just have to see how that does. Not a bad idea to do a compression test while you've got the plugs out. http://www.bassboatcentral.com/smileys/wink.gif

As far as your idle... since you've got the manual already, why not check the "Sync-n-link" settings? In the end, you'll probably end up with idle speed timing somewhere in the 4 degrees AFTER TDC range (+/- 2 degrees). Don't forget to check the TPS as well. http://www.bassboatcentral.com/smileys/wink.gif

Keep in mind, that idle spec is an "in gear, in the water under load at idle" specification. http://www.bassboatcentral.com/smileys/wink.gif

Thanks for the reply!

Do you have an approximate idle speed when on the muffs with no load that "should" get it to the proper in water with load reading?

That's going to depend on your prop (and whether you're running the original gear ratio).

Generally somewhere around 750.

Thanks for the reply!

I am running a 25" Trophy Plus with the original gear case with 1.75:1 ratio. I will adjust the TPS to get the idle around 750 rpm's.

By the way.....can you please explain "sync & link"? I have the Mercury manual (part # 90-822900) and did not see anything referring to that.