Water jacket cover gasket...(or "head" gasket), Mercury 115

[seabob4]

Ryan, I had the same deal with the bottom cylinder on my 700.  No way the gauge fitting was going in that plug hole without removing the lower pan.  But since the other 5 were damn near dead nuts on at 118, I figured 6 would follow through.

My plug wires were toast as well.  Motor basically sat down here in FL for 20 years, the jackets were all cracked.  Farley told me prices for replacement parts was gonna be expensive, he wasn't kidding.  My motor uses a distributor that fires 2 coils, so it has a 2 blade rotor.  Dizzy and rotor are almost $250!!  I can't swing that on what was to me a "free" motor.  I figure by the time I replaced everything that needs replacing, I'd be looking at $1200-$1500.  Uh-uh...

[fitz73222]

On an ADI engine like yours (no distributor) I've never seen the plug wires go bad unless they were damaged some how  . Not enough aftermarket need so Mercury gets to charge what they want! Leave um be...

"Damaged somehow" might describe mine after who knows how long salt water has been spraying on them. The boots are junk, but I can replace those...I was just figuring corrosion may be taking its toll on the wires/ connectors.

You should be able to replace the boots but you may destroy the wire trying to get them off! Spray um down with corrosion block or just put a light coating of dielectric grease inside the boot and rub some on the wire. If it's not miss firing dont worry about it. Unless they're just toasted and go by new ones. You may be able to make your own from 7mm copper core or nickel core automotive bulk wire from the auto parts store, use your old coil boots and get new plug boots. DO NOT USE graphite core wire...

[SaltH2OHokie]

On an ADI engine like yours (no distributor) I've never seen the plug wires go bad unless they were damaged some how  . Not enough aftermarket need so Mercury gets to charge what they want! Leave um be...

"Damaged somehow" might describe mine after who knows how long salt water has been spraying on them. The boots are junk, but I can replace those...I was just figuring corrosion may be taking its toll on the wires/ connectors.

You should be able to replace the boots but you may destroy the wire trying to get them off! Spray um down with corrosion block or just put a light coating of dielectric grease inside the boot and rub some on the wire. If it's not miss firing dont worry about it. Unless they're just toasted and go by new ones. You may be able to make your own from 7mm copper core or nickel core automotive bulk wire from the auto parts store, use your old coil boots and get new plug boots. DO NOT USE graphite core wire...

No, my stumbles feel like fuel stumbles...plug wires to remain as-is for the moment...I'll rebuild the carbs, fix my "water from the spark plugs" trick and check my timing and go from there...

[fitz73222]

You mean the engine hesitates off idle when you put the coals to it? What plugs are in it? Should be NGK BUHW's, Thats what it came with, good plugs...

[SaltH2OHokie]

You mean the engine hesitates off idle when you put the coals to it? What plugs are in it? Should be NGK BUHW's, Thats what it came with, good plugs...

Yep, 6 of those plugs were installed about 3hrs of runtime ago.  No, doesn't hesitate or bog off idle, more like around mid-throttle to 3/4 throttle, it sorta hesitates and surges a little.   Almost feels like you're ever-so-slightly bumping bottom...Tach needles fluctuates accordingly.  My limited experience says: Carb issue.

[fitz73222]

I mentioned this earlier, you have what are called "back drag" carbs; which intentionally lean the fuel flow right in the mid range you are talking about which may be causing the lean surge you describe. The intent was to increase fuel economy at cruise so if the carbs are clean and working right; no harm no foul but if they're not then you get this mid range issue and risk powerhead damage. The diehard inline six wrench heads always plug the bypass hoses off to avoid this lean condition and the carb just acts like a normal carb and maintains a richer mixture in the midrange. In your early powerhead photos, someone has played with them as evidenced by the clear plastic green tube on the upper carb so check those on the other carbs and make sure none are cracked and sucking air. I would replace the small hoses anyway during your carb rebuild or take a suitable BB and plug them off at the fitting where the exit the carb. It will only help to keep the powerhead alive. Maybe your carbs are perfectly fine and this is the true issue.

[SaltH2OHokie]

I'll just be happy when I finally get this old gasket off...I swear the previous knucklehead to work on this motor used JB Weld to try to seal up this water jack leak.  I'm familiar with the taste and feel of JB and this is definitely it.  Funny thing is, I thought it was corroded and they were filling in pitting or crevices, but everywhere I've scraped it off revealed a nice flat surface underneath, so I reckon they just didn't have anything better to use to butter the gasket last go-round.

[Capt. Bob]

I swear the previous knucklehead to work on this motor used JB Weld to try to seal up this water jack leak.  I'm familiar with the taste and feel of JB and this is definitely it.  

Give him a little credit, maybe he used Marine Tex.

[SaltH2OHokie]

I swear the previous knucklehead to work on this motor used JB Weld to try to seal up this water jack leak.  I'm familiar with the taste and feel of JB and this is definitely it.  

Give him a little credit, maybe he used Marine Tex.

I wish he'd have used RTV...I'd have the thing put back together by now...

Tried convincing my wife to take a turn scraping at it Saturday night, but she passed.  

[fitz73222]

And she missed that kind of weird burnt popcorn smell when you start chizeling JB Weld.

[SaltH2OHokie]

Water jacket gasket is replaced.  No one told me I'd be using melted caramel to seal this thing.

Freaking sick of the rain.  I'm pretty sure I could fit the boat in the garage if I got off my lazy butt and cleaned up the garage, but that hasn't happened, so I was under a makeshift trashbag/tarp/tent contraption wearing more layers than I'd have preferred scraping on the block.  The gasket fit, lined up with bolt holes, plug holes, etc, but I can't understand the gasket size/layout compared to the cover/block.  There were extra holes in the gasket sized similar to the sparkplug holes and just offset from them, and there's more meat on the gasket by a large margin than there is sealing surface between the cover and the block.  It's the correct part number and was a Merc/Quicksilver part, so I'm sure I've got the right gasket...just odd to me...

Was planning on pulling the rack of carb's but my bottle of wine was getting low  

Working 2 shifts tomorrow, so definitely not playing with it until maybe Friday afternoon.  Anxious to get the carbs done and see if that cures my woe's.  

I'm going to plug those "economizer" hoses when I do it.  I've also read/been told to pull the jet off of the top/side of the bowl as it was functionless after plugging that circuit.  That seems odd to me, but I've read it enough places to figure it must be acceptable.