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1969 Mercury Tower of Power Gasket Leak

J

Jaybey

Contributing Member
Here we go again...

Seems there's no paper gasket here, just a gasket maker of some sort. My parts engine has the same so I assume that it's supposed to be that way.
However, it is leaking at idle. So I must assume it's leaking like a bastard at WOT haha. The leak is on the starboard side of the engine, right in between the stator connections and the starter mounting bracket. I did find a slightly loose bolt also leaking and torqued it down a bit, but still leaking.

Am I looking at a full tear down and re-seal at this point?

Please see attached video, it's not the clearest but you'll get the gist....

 
Yes I would be tearing that down to see what was done.-----It is crankcase compression.----That little leakage may not be a problem at full throttle.
 
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There is no gasket there.----But I have seen a film of sealer there that was 0.008" thick.-----That sealer should be less than 0.001".------Assemblers can be careless / uneducated.
 
thanks for the quick reply!

So I'll just tear it down, clean it up and use what if anything for a sealant? I'm assuming it's gas mixture leaking there, it wouldn't be water would it? The bubbles seemed too small to be water. Usually gas being so thin will create small bubbles like that right?

Anything else I should consider doing while I that deep into it?
 
It's definitely gas, just tore my 67' 500 apart for the same reason. The sealant you want the use is loctite 518, it's a red sealant/gasket maker. A very thin layer on one of the housings being cautious that both surfaces are clean with no oil or debris
 
Thank you damien, I guess symptoms this could cause would be poor functionality of the cylinder bleed check valve system leading to a poor idle? Due to the loss of crankcase pressure? I'm pretty sure the engine has been running in this state for a long time, the block was yellow orange with evaporated fuel mixture stuck to it. I've since given it a bath (hours of detailing with carb cleaner, shop towels and cue-tips), so it actually looks new again. I've since done a full fuel system overhaul and hope to get it to the lake for a trial run, so I'm thinking this procedure might be a good winter project. I tend to rush things in season because I want to be back on the lake! ��
 
Is the leakage in just one little area?-----If yes that using a round nose punch amd a hammer may move the aluminum to seal the leak untill you decide to take it apart.-----Is the factory lead seal still on one of the bolts on that joint ?
 
There's a lead seal, though not factory (missing the Kiekhaefer stamp). I had a local retired merc mechanic look it over upon purchase and he said it had been apart, but they'd done a nice job buttoning it back together. Clean work, aside from this leak that is..
 
In my opinion if it's leaking externally how much internal back pressure is also leaking between all the cylinders causing an improper running engine. Taking your time is definitely the key to a proper overhaul. While apart I honed my cylinders and replaced the piston rings just to ensure a tight seal.
 
Fair enough.. I can't help but wonder what effects any unseen further leaking is having also. I'm reading between 125 and 130 psi on all six now, but that that has nothing to do with crankcase pressure...
 
This joint is a " precision fit "------Properly done it clamps tight the reed blocks and bearings .-----If the reeds blocks / bearings are a bit loose in there , there will be issues later.-------I have seen what results when reed blocks are loose !!
 
Oh boy... ok, so I've been experiencing trouble with not being able to get over 4k rpm at WOT. Hence the fuel system overhaul. I've also noticed while doing so and cleaning the block that my primary and secondary throttle pickup is out of adjustment (butterflies start opening immediately when throttling up), I've since stated a new thread seeking info on the timing degree settings for my model to check first of all, that the spark advance is properly set to the right degrees so I can then set the throttle pickup properly. But! Could the improperly seated/loose reed block or bearings cause this issue as well? Might also be worth that when doing a de-carb with mercury engine tune I noticed that there was little to no change when spraying into the top carb.. though I've verified spark on all plugs.
 
Well-----Something is wrong if spraying into the top carburetor does not change sound.-------I would stop running this motor until you sort out the problems.-----No fuel going into the top 2 cylinders due to the top carburetor being plugged means no oil.-----Motor might go ----" BOOM " and come to a " dynamic halt " ----Big $$ to repair if you can find the parts when it goes " boom ".
 
Right you are Racerone.

I plan on spraying into the carbs to test again this evening now that they're are cleaned with new kits installed.

I'll post whether it's made a difference or not. If not, what could it then be? I've rebuilt the fuel pumps as well as changed all the lines and fittings, though I've reused the existing check valves (local marina got the wrong kits), but they seemed in decent functional shape so...
 
Ok...

So I ran the engine in the driveway tonight, warmed it at about 1400 rpm then sprayed tuner into the carbs one at a time. STILL no change on the upper carb!

I'm starting to get discouraged here

Now all I can think is maybe a stuck reed block...?

I can jump a half inch with spark on 1 and 2, the fuel system has been completely overhauled. Number 1 plug came out dry and cool comparatively speaking.. all the rest were somewhat wet and warm.

Another thing, though the spray didn't dain out the front of the carb.. I did hold my hand in front of all three while running. With the grill in place it was hard to feel the suction, but on the center and bottom ones I could just feel the air rushing past and tickling my finger hair haha. Not so on the top one. This also tells me reeds.

I'm at a loss. I have a somewhat complete parts motor, but do I really want to reuse old reeds??
 
So I pulled the top carb today and the reeds in front are free and seam seated ok for both 1 and 2 cylinders. I can't however see or reach the ones in back.

I was able to blow smoke through the crankcase opening and it came out the plug holes.

What if anything does that indicate?
 
Now that's something I would've never though of.. doesn't that sound like a bit of a suicide mission? Might I be so bold as to ask your thought process behind your suggestion?

Respectfully of course, I've seen your posts dating back years and years. You've helped a whole lot of people man.... just want to understand is all

I'm a full time musician, and I'm gigging in a small town in Quebec this weekend at a festival as the house band.. when I get home Sunday night I'd be willing to give it try
 
I've seen a similar condition on one of my Merc triples (which are one half of a your motor). Going along on plane, and not making anywhere near full power, I 'hand choked' the lower carb by inserting my fingers into it. Motor immediately responded with a blast of full power...until I removed my fingers. It then died way down again.

Obviously a lean out condition, but why? All I can surmise is that it had a massive vacuum leak at the crankcase-block joint (though I saw no evidence this was possible upon teardown. The lower seals were in good condition as well.)

Go figure!

Jeff
 
Simple thing to try.------Nothing will go " boom " on your motor !!-----Why would you use the term " suicide mission " here ????
 
racerone said:
Simple thing to try.------Nothing will go " boom " on your motor !!-----Why would you use the term " suicide mission " here ????
Click to expand...

Hey Racerone,

I used the term only as a cautious description here.. to me, wiring the plugs incorrectly on any motor puts in mind pistons firing at the wrong time possibly creating a catastrophic failure inside. Hence why I asked for some clarification on the suggestion.

No offense was intended mister..
 
fastjeff said:
I've seen a similar condition on one of my Merc triples (which are one half of a your motor). Going along on plane, and not making anywhere near full power, I 'hand choked' the lower carb by inserting my fingers into it. Motor immediately responded with a blast of full power...until I removed my fingers. It then died way down again.

Obviously a lean out condition, but why? All I can surmise is that it had a massive vacuum leak at the crankcase-block joint (though I saw no evidence this was possible upon teardown. The lower seals were in good condition as well.)

Go figure!

Jeff
Click to expand...

This is my thought as well, my leak (what can be seen anyway) is visible. I guess I'm going to have to tear it down after all. I've never ventured into such territory on an engine before, kinda intimidating..

I'll likely try racerone's suggestion first however... if it works I'll be golden
 
racerone said:
Try changing plug wires around.----Put #1 on #2 cylinder.
Click to expand...

You know.. in my defense, I've heard horror stories in the past of guys accidentally reversing spark plug wires and destroying their engine. With absolutely no explanation at all to elaborate on what your intentions were with this statement, I mean really.. why wouldn't I (or anyone) question this option??

I kinda feel like I've been put out to dry here. I've been nothing but courteous and grateful for the advice and information you guys have graciously provided me here. I think it's just fantastic. But let's face it, this is the internet. And you really need to be careful about what you read... one needs to keep an eye open and question things sometimes. Don't you think?

I don't think I was out of line to ask. The word suicide was used loosely and descriptively. I'm sorry if it hit a sore spot for you. But I do believe you're being a little sensitive here.

Just maybe?
 
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