'98 Merc 25 Squeak

Discussion in 'Outboard Maintenance' started by rkmurphy, May 7, 2009.

  1. rkmurphy

    rkmurphy Well-Known Member

    Decided to start a new thread as the old topic was kind of away from the current issue.

    A little update...I ran the boat today at a lake and I noticed 2 things:

    1) It was pissing sh*tty again and the pee stream was lava
    2) It was still squeaking after a WOT run

    I headed back in making sure the motor wasn't overheating, which it wasn't. When I got back to the house I took the "filters" off of the lower unit and took a hose to the pee tube on the motor. I put the hose sprayer on the "jet" setting and shot it through for a couple of minutes. I reinstalled the "filters" to the LU and hooked it up to muffs. The motor pees fine now. I ran it for at least 20 minutes, increasing the rpm's sometimes. Seems good now.

    Next issue is the squeak. When I was heading in to the ramp I had my fiance steer and I listened in on the motor. It's not coming from the motor at all. In fact, it sounds like it's coming from either the exhaust housing or the lower unit. I checked the gear oil and it looked fine. Now, the question is, what could be causing a squeak from an exhaust housing or LU ONLY when coming off of WOT?
  2. Brett

    Brett > PRO STAFF <

    Metal on metal, the reverse lock bar might be loose and rubbing?
    Slowing down puts drag on the lower unit and pulls the motor
    away from the transom, somethings loose and moves, squeak...

    or maybe you trapped a mouse in there... ;)

  3. islander1225

    islander1225 Well-Known Member

    sounds like to me it is just sounding like a good ole 2 stroke lol.

  4. rkmurphy

    rkmurphy Well-Known Member

    I called Bud's to see if they were eating cheese when they pulled the lower unit. He said no :(. Which is really frustrating because that would have been a simple issue to solve.

    Anyone else have any thoughts?
  5. Un-shore

    Un-shore Well-Known Member

    Loose motor mounts?

    Did you say you replaced to impeller since the squeeking started?
  6. rkmurphy

    rkmurphy Well-Known Member

    Yes I did replace the impeller.  How would I check for loose motor mounts?  It does seem to shake excessively at idle...

    Edit: Spoke with AFA Marine today since they always seem to be the most knowledgeable...I hate pestering them with my issues all of the time, though. Anyhow, he just said to not worry about it...it may just be a sound the motor makes. "If it's gonna blow up, it's gonna blow up and there's not anything any mechanic can do about it but rip the motor apart to see what may be wrong." He said it's probably nothing, though.

    Anyways...looks like you may be right, Alex. That's the second time that you've been right about my motor now. Haha.

    I'd still like to know how to check the motor mounts, though.
  7. Un-shore

    Un-shore Well-Known Member

    motor mounts #3 and #20 ;http://www.marinepartsplus.com/catalog/mercury/serial/25/+99917/1138-120

    Look for obvious wear and eccessive play. A good test is spray a little armor all on them and see if the squeeking stops. A worn or broken mount could be hazardous to your health. :(
  8. rkmurphy

    rkmurphy Well-Known Member

    What about WD-40? Could I test it with that or would WD-40 be bad for the mount?
  9. Un-shore

    Un-shore Well-Known Member

    I think wd would be okay.
  10. rkmurphy

    rkmurphy Well-Known Member

    Ran the boat today and didn't squeak all day until I opened it up on the way back. The squeak is fairly loud and if I "bump" it with a little bit of throttle (just a quick on and off) while I'm idling it gets louder and even chirps a little bit (very rapidly...so I don't think it would be a sneeze). It eventually fades off.

    It runs great, though, and doesn't seem to be overheating. I shot some silicone spray on the lower motor mounts and up and down the drive shaft (from the small, tiny area where it's visible), just for sh*ts and giggles.

    Anyway, keep the thoughts coming.

    I took the cowling off and I guess the spark plugs weren't tight enough (barely finger tight) because gas/oil was leaking out of them (not quickly or anything). I inspected the plugs and they look really good...not fowled or anything, as I compared them to that chart someone sent me on another thread (B. Lee, I think). I did notice this yellow ring around the base of the plastic part that says "Autolite".

    Here's some crappy pics:




    Not sure what this is...but would like to know :).

    Thanks everyone for your help so far.
  11. Brett

    Brett > PRO STAFF <

    The discoloration looks like cooked lubricant, WD 40 maybe?
    Spark plugs are meant to be torqued in place to the proper specs.
  12. rkmurphy

    rkmurphy Well-Known Member

    Possibly WD-40 or whatever the mechanic had on his hands when he repaired my thermostat.

    I torqued down the plug according to the repair manuals instructions.  Should be fine, now.
  13. Un-shore

    Un-shore Well-Known Member

    did the chirping sound stop after you tightened the plugs?
  14. rkmurphy

    rkmurphy Well-Known Member

    I'm not sure yet.  Won't be able to run it til the end of the week.  I think I'm going to SeaFoam blast it and replace the gear lube before I take it out.  Then I'll run the piss out of it.  :)


    Just bought a can of SeaFoam and bottle Quicksilver gear lube. I also returned the Attwood fuel tank as it was just plain crap. I'm going to run by West Marine tomorrow and get a Moeller tank and tank fitting as well as some Quicksilver Power Tune. I'm going to do the whole process that whitesnooky went through on his Merc 25. Mine could probably use an inner cleansing, anyway. I figure ~$10-$12 to try to fix the issue couldn't hurt.

    I also checked the compression and both cylinders are ~130psi. The top was maybe 2 psi lower but I'm guessing that means absolutely nothing.

    I'm also going to replace the gear lube and screw gaskets as I'm just not satisfied with how my last job went. Again...cheap precaution.

    I'll do all of this stuff Friday and as soon as I'm done Seafoaming her, I'll take her to the local lake with some fresh gas/oil/StaBil and run her like hell.

    I just want to get this issue squared away...I may be a hypochondriac but I just don't have a good feeling leaving it the way it is.
  15. rkmurphy

    rkmurphy Well-Known Member

    I just wanted to clarify why I'm worried about it running lean at top end. I made a previous post about my first outing at CRB when I opened it up on the way back in. After I did that, it started to squeak, as usual. I went to give it some throttle and it made a pop with a puff of smoke out of the exhaust and the squeak stopped.

    Now, I don't know much about this but I'm guessing that maybe the main jet is letting enough fuel mix through at cruising speeds but is maybe just a little plugged up to only affect top end where it's just not letting quite enough fuel through. That's just my uneducated theory :-?.
  16. grego

    grego Well-Known Member

    I have a merc 60 on my boat. Now and then it will "chirp" for a short period then stop. Its been doing it since I bought the skiff. It might just be a merc thing.
  17. hardin083

    hardin083 Well-Known Member

    I have an 03 merc 25 two smoke, and just 3 days ago i noticed a small chirp while running wot.. i came off a plane to an idle and it still had a small chirp :-? shut down to fish and when i fired it back up the problem was gone and i haven't noticed it since.. but ive only had it out one time since..
    i think you cursed me being how it happened after i read this thread :mad: ;) or maybe i never paid enough attention , but oh well ill just keep running the dog crap out of it  ;D ;D
  18. iMacattack

    iMacattack busy, too busy

    both of my old Merc 25's had a little chirp... unless it becomes a squeal I'd run the snot out of it and wait for it to go bloom!
  19. Brett

    Brett > PRO STAFF <

    I 'm thinking you're hearing the noise coming from the exhaust relief holes, located as shown circled in red in this image.
    Exhaust gases passing through the small diameter holes, will make some interesting noises.
    And if some exhaust crud has built up in the passage way, might make the noises you're hearing

  20. iMacattack

    iMacattack busy, too busy

    I would concur, when I have crud in my exhaust relief hole, I get some funny noises too... plus a weird oder... ;D

    Sorry I couldn't resist... sorry for the [smiley=no_derail.png]

    Back to topic now...