Tuneup make *that* big a difference?

[KRS]

I haven't done a tuneup since two seasons ago and my 2.5 mercruiser is running rough.

I have always wondered... does new plugs, wires, cap, rotor and condensor make THAT big of a difference???

Seems like a silly question, but I'm serious.

Thank you.

 

[MRS]

Re: Tuneup make *that* big a difference?

Yes it does.................... it is way easier to do in the driveway than to be towed in and do at the marina.:'(

 

[Don S]

Re: Tuneup make *that* big a difference?

In a word, YES.

Do your complete tuneup, set dwell, timing, check advance timing, adjust idle mixture, set everything to specs and do a test run.
Since a 2.5 is an older engine, even doing a proper compression test each year would be good information to have over time. You could see what is going on.
If you fog your engine during the off season, the oil sits on the plugs porcelen (sp) and causes them not to work as well after the LONG wait.
Look at the tracking where the cap and rotor passes spark. Plug wires may be fine, inspect them and test if you have a misfire, but unless they show problems, it's not necessary to replace them.
Points, come on, after sitting for a few months, they need replaced. Which involves dwell and timing.

 

[KRS]

Re: Tuneup make *that* big a difference?

Thank you for the replies.

I did fog the engine pretty good when I put it up.

I'll figure out the parts I need and give it a try... and then I'll try to remember to post a follow-up.

Thank you.

 

[DHPMARINE]

Re: Tuneup make *that* big a difference?

I have to wonder when you did a waterpump last??

DHP

 

[KRS]

Re: Tuneup make *that* big a difference?

I've never done an impeller... a marine mechanic did mine a couple seasons ago.

Once I watch someone do something, I can do it no problem. But I don't like to try and learn from a manual. If I can ever watch someone do an impeller, put in a set of points, and adjust the dwell and timing.... THAN I would have no reservations doing these things myself.

 

[KRS]

Re: Tuneup make *that* big a difference?

Pulled dist cap and rotor, there was some wear and scoring... I was surprised. I feel that I use my boat very little compared to some.

I do not know anything about points (shoulda taken auto shop in high school), so I'll say they looked good. I'll look into replacing them as suggested above.

Plugs were a little dirty, wiped them clean.

Restarted the boat and it ran a little better (cleaned scoring from inside cap and plugs).

With fresh gas and an actual tuneup as described above it should be running excellent again.... Thank you all for your help.

 

[flashback]

Re: Tuneup make *that* big a difference?

hey Don, why do you suggest replacing points after sitting for 3 months? Is it spring fatigue? d not trying to be a smart a$$. I really would like to know...thanks

 

[Don S]

Re: Tuneup make *that* big a difference?

Take a new set of points, measure the resistance thru the contact points. Run the points for a year, winterize, and in the spring remeasure. The higher the resistance, the lower the spark output. Just sitting for 6 months in that distributor will cause corrosion and higher resistance.
Boats run at a lot higher rpm than cars and the higher the resistance, the lower the spark output. While the engine may still run, it won't be near as effecient as it is with new points, and plugs. The fuel you waste just from using used plugs and points will pay for the parts. Plus your engine will run better and there won't be any of those July and August posts about the rpm not going above 3000-3500 rpm.

 

[KRS]

Re: Tuneup make *that* big a difference?

Almost sounds like the $189 electronic conversion for the distributor would be a good way to go

 

[DJ]

Re: Tuneup make *that* big a difference?

Don S is correct, on the points, cap and rotor.

Not to mention, those points are sitting in a pretty nasty environment, compared to what they used to do in cars.

I think the electronic is the way to go too. The ONLY issue that when it doesn't work, it doesn't work. No "fiddling" will make it limp home. But that's old school thinking.

 

[KRS]

Re: Tuneup make *that* big a difference?

I suppose the points pieces could be kept in a small bag in the boat toolbox just in case

 

[Tail_Gunner]

Re: Tuneup make *that* big a difference?

Point's, that sure bring's back memories. If you could get 10000-15000 miles on a preformance car you were doing good, Carrying a spare set? dont forget how important dwell is........ usally you could just file the points down a tad.....that is just roughing up the surface gap. That sure be a lot eaiser than installing them again and trying to set the dwell on open water........... Id just carry a emory stick easy quick and effective in a tight pinch.

 

[flashback]

Re: Tuneup make *that* big a difference?

thanks for the info Don, I have a spare set of points in the boat. guess I'll put em in next spring.. as a matter of fact, I guess I'm a bit anal, but I carry a spare fuel pump, filter, plugs, belts, and a section of hose that is long enough to replace the longest hose in the cooling system..I've never needed anything but a belt for the water pumpd, but I was sure glad I had it.....d

 

[DJ]

Re: Tuneup make *that* big a difference?

My philophy is that "if you have a spare" nothing will break.