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  1. #1
    Join Date
    Jun 2008
    Location
    Island Heights, NJ,
    Posts
    2,574

    Default "Ok, so I finally get to take

    "Ok, so I finally get to take the wife out fishing last week after a very late in the season launch and on the way back the engine starts running rough. Very dis-inclined to run under 1500 RPMs. Docking was fun.

    I checked the fuel filter, no water, but I replaced it anyway as it was due to get changed anyway. I checked the cap and it was a bit cruddy, as was the rotor. Replaced both. I scribed two lines on the rim of the distributor to match up with the rotor contact to make sure new rotor went back on correctly. Replaced the plugs. Old ones looked OK with no buildup but some reddish brown deposits on one side of the insulators.

    I started the engine and it ran reasonably OK while warming up, i.e., until the enrichment circuit cut out (stopped audible hissing), then the engine started to stumble and the RPMs dropped, then it stalled completely. I shut the fuel valve off and still had the same problem, so its not a leaky float valve. It will run sorta OK if the enrichment circuit is on.

    I set the engine to base timing mode and it looks like its 16 degrees. Was surprised to see it that far off, as distributor lock down was never touched, and the toothed sensor of the rotor is the same one as was on the engine before. Tried to set it to 10 degrees, but could not get engine to run long enough to do that. It's somewhere between 10 and 16 now...however, the mystery of the 6 degree difference from a rotor change is.... a mystery.
    Did not have time to wait for enrichment circuit to reset itself as it was getting dark and looking like a T'storm.

    I tried to find the idle mixture adjustment, but there apparently isn't one on this circa 2005 engine?

    It's starting to look to me like crud in the idle circuit of the carb, however, tearing the carb apart means getting a new gasket and the nearest source is a 25 mile each way drive.
    Does the blue permatex work OK as carb gasket replacement? I can never quite bring myself to trust the stuff.

    I double checked the firing order and double checked that all plug connections are OK at each end. Engine has fresh fuel. Very low hours on engine... 30 hrs."
    Capt Bob
    1969 23ft ChrisCraft Lancer
    Merc 5.7L 260HP/ Volvo 280
    1972 22ft Bristol
    Honda 7.5HP 4 stroke Long shaft

  2. #2
    Join Date
    Aug 2006
    Location
    SW Ohio, USA
    Posts
    10,396

    Default "Replaced the plugs. Old o

    "Replaced the plugs. Old ones looked OK with no buildup but some reddish brown deposits on one side of the insulators."

    What have you been adding to your fuel? Octane booster?
    Fix minor things (replace wear items for preventative maintenance.) that cause major problems before they break.

  3. #3
    Join Date
    Jun 2008
    Location
    Island Heights, NJ,
    Posts
    2,574

    Default Straight from the local gas &#

    Straight from the local gas (non marine) station pump... Had run about 20 gals with the stuff that is supposed to prevent/remedy phase seperation. Engine supposed to run on 87... I usually feed it "plus" (midgrade)
    Capt Bob
    1969 23ft ChrisCraft Lancer
    Merc 5.7L 260HP/ Volvo 280
    1972 22ft Bristol
    Honda 7.5HP 4 stroke Long shaft

  4. #4
    Join Date
    Aug 2006
    Location
    SW Ohio, USA
    Posts
    10,396

    Default Is the engine fueled w/a TKS c

    Is the engine fueled w/a TKS carb?
    Fix minor things (replace wear items for preventative maintenance.) that cause major problems before they break.

  5. #5
    Join Date
    Jun 2008
    Location
    Island Heights, NJ,
    Posts
    2,574

    Default Yep...

    Yep...
    Capt Bob
    1969 23ft ChrisCraft Lancer
    Merc 5.7L 260HP/ Volvo 280
    1972 22ft Bristol
    Honda 7.5HP 4 stroke Long shaft

  6. #6
    Join Date
    Aug 2006
    Location
    SW Ohio, USA
    Posts
    10,396

    Default "It will run sorta OK if t

    "It will run sorta OK if the enrichment circuit is on."

    Perhaps you should get a carb kit and rebuild it since it won't idle. I keep a roll of gasket material in the event I need to make one. I lay the material over the item and gently tap on the material w/a small hammer to outline the gasket and then cut it out w/an exacto knife or small razor knife.
    Fix minor things (replace wear items for preventative maintenance.) that cause major problems before they break.

  7. #7
    Join Date
    Jun 2008
    Location
    Island Heights, NJ,
    Posts
    2,574

    Default I was afraid you were going to

    I was afraid you were going to say that. Looks like a carb redo is going to be an every other year event so long as they are pumping s$%##t for gas. Last rebuild was two seasons ago when the engine had 5 hrs on it. Its sad when you get more time out of a set of plugs than a carb rebuild.
    Capt Bob
    1969 23ft ChrisCraft Lancer
    Merc 5.7L 260HP/ Volvo 280
    1972 22ft Bristol
    Honda 7.5HP 4 stroke Long shaft

  8. #8
    Join Date
    Aug 2006
    Location
    SW Ohio, USA
    Posts
    10,396

    Default Start using a can of SeaFoam w

    Start using a can of SeaFoam w/each fill-up. If you have a canister type fuel filter you can empty the gas and fill it w/SeaFoam. Run the engine 5 mins. and let it sit o'nite. If it helps some then repeat it.
    Fix minor things (replace wear items for preventative maintenance.) that cause major problems before they break.

  9. #9
    Join Date
    Jun 2008
    Location
    Island Heights, NJ,
    Posts
    2,574

    Default "I've got the standard spi

    "I've got the standard spin on fuel filter/water sep. Worth a try w/seafoam. Thanks !!!

    BTW... any idea why the timing was so far off from just changing the rotor? A visual inspection of the keyway in the rotor showed it to be pretty much in the same place in th enew one as on the rotor I removed... and no, I'd never checked the base timing on the engine before that, so its always possible its always been 6 degrees off... and yes, it is going into base mode as timing is even more advanced with the ground clip off the purp/wh lead... and paint marks on dist hold down bolt indicate it had never been touched. I've never owned a MERC engine before, so I guess I get to learn the foibles of yet another engine."
    Capt Bob
    1969 23ft ChrisCraft Lancer
    Merc 5.7L 260HP/ Volvo 280
    1972 22ft Bristol
    Honda 7.5HP 4 stroke Long shaft

  10. #10
    Join Date
    Jun 2008
    Location
    Island Heights, NJ,
    Posts
    2,574

    Default "UPDATE... LAst night I start

    "UPDATE... LAst night I started the engine and waited until it was almost warmed up. Pulled the filter, drained it (clean) and filled it with Sea Foam. Started the engine and ran it until I saw white smoke. I kept it running for awhile, then shut it off.

    This a.m. in a lull between thunderstorms, I started the engine. It did not want to run on a diet high in SEAFOAM ( as evidenced by more white smoke and a lot of stumbling). I played with the throttle and kept it running at 1300 until it started to warm up (its A FWC engine, so it warms nicely). When the enrichment circuit cut out it continued to run (at 600-700) but not all that happily, but most importantly hands off the throttle!!!
    It started to pour rain again, soooo... later I'll dump the rest of the SEAFOM into the filter and try again. Fortunately, it was on sale at "Advance Auto Parts""
    Capt Bob
    1969 23ft ChrisCraft Lancer
    Merc 5.7L 260HP/ Volvo 280
    1972 22ft Bristol
    Honda 7.5HP 4 stroke Long shaft

  11. #11
    Join Date
    Aug 2006
    Location
    SW Ohio, USA
    Posts
    10,396

    Default You just cleaned the carbon fr

    You just cleaned the carbon from the valves and combustion chambers. Let it work on the carb fuel passages o'nite again. It is some good stuff!
    Fix minor things (replace wear items for preventative maintenance.) that cause major problems before they break.

  12. #12
    Join Date
    Jun 2008
    Location
    Island Heights, NJ,
    Posts
    2,574

    Default "Frankly, I was amazed at how

    "Frankly, I was amazed at how well it worked on only one shot. Soon as it stops raining here in NJ, I'll pour the rest of the can into the filter."
    Capt Bob
    1969 23ft ChrisCraft Lancer
    Merc 5.7L 260HP/ Volvo 280
    1972 22ft Bristol
    Honda 7.5HP 4 stroke Long shaft

  13. #13
    Join Date
    Aug 2006
    Location
    SW Ohio, USA
    Posts
    10,396

    Default Run it for 3-4 mins. and shut

    Run it for 3-4 mins. and shut it off. The carb bowl and passages will be full and clean out the crap overnight. Get it out and run the crap out of it Sat.
    Fix minor things (replace wear items for preventative maintenance.) that cause major problems before they break.

  14. #14
    Join Date
    Jun 2008
    Location
    Island Heights, NJ,
    Posts
    2,574

    Default "UPDATE: Did that... not muc

    "UPDATE: Did that... not much difference.
    So, I decided to bite the bullet and pull the carb off the engine so I can work on it at home in comfort. To my surprise, when I took the carb off there was a spacer between it and the manifold (not the surprise). It was a regular, i.e., not tapered/wedge spacer. The surprise came when I read the molded-in words "Front of Engine" on the spacer... and it was facing the back! I looked down the bore and saw that the reason for this is that the bores of the carbs are not quite "square" to the mounting bolts, and I could see an offset in the manifold bore to the spacer. In other words, the carb and the manifold bores lined up, but the spacer was offset about a 16th of an inch leaving a "lip" in the passage. Nothing like a little turbulance on the way to the intake ports!

    I've been wondering about the incorrect static timing and beating myself up that I somehow improperly installed the rotor, now, I just think that MERCRUISE has some QC problems, which on this engine so far includes: timing off, carb spacer incorrectly installed.... and the night is young!"
    Capt Bob
    1969 23ft ChrisCraft Lancer
    Merc 5.7L 260HP/ Volvo 280
    1972 22ft Bristol
    Honda 7.5HP 4 stroke Long shaft

  15. #15
    Join Date
    Oct 2008
    Location
    Lakewood, NY USA
    Posts
    317

    Default "Rob, Is your engine factor

    "Rob,

    Is your engine factory new?? Man that is pretty bad QC?? Whats up with that"

  16. #16
    Join Date
    Jun 2008
    Location
    Island Heights, NJ,
    Posts
    2,574

    Default "Factory new... When I took o

    "Factory new... When I took off the carb, my wrench broke the paint off the nuts, likewise with the holddown on the dist when I reset the timing.

    While I'm thinking about it.
    QC problem #3: Over tightened holddown bolt on the dist. I should not have had to put an extension on the handle of my wrench to apply enough force to "break" the holddown bolt free."
    Capt Bob
    1969 23ft ChrisCraft Lancer
    Merc 5.7L 260HP/ Volvo 280
    1972 22ft Bristol
    Honda 7.5HP 4 stroke Long shaft

  17. #17
    Join Date
    Oct 2008
    Location
    Lakewood, NY USA
    Posts
    317

    Default "Wow, It must of been made

    "Wow,

    It must of been made on a Friday afternoon on memorial day weekend and everybody lost too many brain cells at the factory that weekend and forgot where they were in the process of building YOUR engine!!"

  18. #18
    Join Date
    Jun 2008
    Location
    Island Heights, NJ,
    Posts
    2,574

    Default "Update... MAY have found the

    "Update... MAY have found the problem, BUT...
    Yesterday I took a close look at the carb (trying to find the P/N) and discoverd two things.

    1) Not only was the spacer on backwards, but the carb gasket was as well. ( not an issue)
    2) I discovered a small piece of metal shaving trapped between the tip of the idle mixture screw where it protrudes from the idle mixture "hole" and the hole itself! It obscured about 20 to 25% of the annular clearance between the mixture screw and the hole. This morning I got dental pick and tried to get the chip out. I did, but unfortunately as soon as I touched the chip with the pick, it dropped back into the idle mixture passage. Thought I... "OK, I'll screw the mixture screw all the way in, counting the turns, then remove the screw totally and if I'm lucky, the chip will shake out!"

    Then I looked at the "adjustment end" of the idle mixture screw. WTF!!! There is a baffle with a hole in the middle of it and looking beyond that where I would expect to see a screw, I see a piece of metal sticking up whose end is coated in paint.

    Where do I go from here??? Chip paint off and find a screw slot underneath??? Do I have to remove the baffle to get the mixture screw all the way out??? MERC manual is silent on this."
    Capt Bob
    1969 23ft ChrisCraft Lancer
    Merc 5.7L 260HP/ Volvo 280
    1972 22ft Bristol
    Honda 7.5HP 4 stroke Long shaft

  19. #19
    Join Date
    Jun 2008
    Location
    Island Heights, NJ,
    Posts
    2,574

    Default "Well, I got lucky... found a

    "Well, I got lucky... found a new gasket only 10 miles away. Re: that "chip" that I saw trapped between the idle needle and the passage. In the process of taking things apart, I dropped the carb (only an inch or two) and lo and behold, that chip reappeared. After several trys, I was able (using a miniature jewelers screwdriver as a pick) to pull it out thru the passage into the throat. Still going to give it a good cleaning...

    Noticed two things on-line... They make and sell
    a) "reusable" carb bowl gaskets for a number of cars. The material is "buna-n"
    b) You can buy a sheet of 12 x 12 x 0.1" buna-n online for about $10.

    Next time....This time, I'm feeding my gasket to my flat bed scanner (with a machinist's scale on the bed as well) before I put it on the carb."
    Capt Bob
    1969 23ft ChrisCraft Lancer
    Merc 5.7L 260HP/ Volvo 280
    1972 22ft Bristol
    Honda 7.5HP 4 stroke Long shaft

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