25 hp merc issues

[slotfish]

Hey All,
Okay, this has been going on too long and finally I'm going to ask for advise, especially since I don't know anything about motors (the first step is admitting it)! My 1994 25hp merc has amazingly frustrating behavior. Sometimes it starts okay and others not at all, I mean hopeless yanking on the rope with out even a sputter.
When it does run, it will restart if I shut it off, but if it kills itself, forget about it. It also has a very unpredictable idle. It tends to kill while (slow)trolling and last year I had to be towed off the lake. I've tried new plugs, heating the plugs, etc. Any info about possible problems/remedies would be greatly appreciated before I have a heart-attack over this thing.

Thanks

[perchpro]

sounds like you have some carb issues. try running a can of sea-foam thru it, and if that dosen't help bring it in to a dealer. they should find the problem and fix it for a little cash.

[da king]

pearchpro has a point the carbs should be tuned,also how is your gas line and fittings i had a 91 merc and it was the most relible bullet proof motor ever until i tried those after market hoses and fittings then the thing ran like dump!! went to dealer and got the merc. fittings and hose then it was back to being the awsome motor that it allway's was!! good luck hope you figure it out

[Ybone]

Could be a sticky intake needle valve especially if it dies shortly after you first start it and then won't restart. If that's the case the ball will get real hard after squeezing it. You can sometimes restart by squeezing the ball hard til you feel it break loose and opens the stuck valve so you can pump gas to the carb.

[Guest]

Sounds like a fuel pump problem to me. Should be a easy fix. Wouldn't hurt to put a new one in anyways.
Had that same problem in a Johnson 60 last year. Unpredicable and left me stranded. It wouldn't start one day....the next ran fine until you shut it off or idle for awhile.

[This message has been edited by CD (edited 06-27-2002).]

[Guest]

If the engine "pops" while it's running, and it seems to be getting plenty of fuel....the points and condensors might be bad. Friend of mine just replaced his points/condensors yesterday in his 25hp. His motor was very unpredicable and "popped" as it ran. Sometimes it would just die and wouldn't start, other times would run ok.

[SteveR]

I have a 89 25 horse Merc and two years ago I was up on Winnie and the darn thing just decided not to run. Pull and Pull and Pull. Let it sit for a while and try again I could get it to go, put it in gear and went about 20 feet and done again, pull and pull and pull. Nothing. Took it to a local mechanic - paid $50.00 for a clean the carb job - ran good - for one day. (this was geting to be the worst week I ever had up there) I sat by the dock pulling my @$$ off when an intelligent gentleman came down and said it seemed to him there might be something plugging the jets. Pull off the lid and cover the carbureter intake so as to totally choke it. Smother it. It might pull whatever through. I did, it did, works great! Happened one more time to me last year. I did the same. Worked great. I have been saying that I was going put some type of in line filter on my tank, haven't done it yet, but I bet it will stop the problem for good. Maybe this will help.