Mark 58 - how do I clean the water jacket?

[new2mercs]

The Mark 58/58A that I'm slowly bringing back to life fires up and runs, but despite a new impeller I don't get any water out the pee hole. I'm reasonably confident that it's pumping, since it doesn't show any sign of overheating and I'm seeing water here and there at the top of the driveshaft housing.

Is the main access to the water jacket through the large cover on the port side of the powerhead? I believe the starboard-side covers are for the transfer ports and won't give much access. Also, is this motor end-bored (if that's the right word) -- in other words, is the plate that the spark plugs thread into a head, or just a cover?

I'm thinking that there's a bunch of crud in the water jacket that needs to be cleaned out, but I'm hesitant to start pulling off covers without knowing for sure what's under them -- especially after seeing a lot of warnings on the forum about easily broken bolts... .

 

[Laddies]

Re: Mark 58 - how do I clean the water jacket?

Your right the port side cover is the exhaust plate, the rear cover is a water jacket cover. It was common for those engines to plug up under the power head and the power head had to be remove to clean it, also if the exhaust side plugs the engine will usually over heat. If you remove the power head to check and there is not a restriction it also make the other plates easier to get too.

 

[new2mercs]

Re: Mark 58 - how do I clean the water jacket?

Thanks (again) Laddies!

I'm thinking about hitting each bolt head with the OA torch long enough to get it dull red or so, then letting everything cool down, in hopes that I can avoid breaking bolts. Good idea? Bad idea?

 

[turbinedoctor]

Re: Mark 58 - how do I clean the water jacket?

You may want to pull the tell tale hose and fitting where it attaches to the motor to check for blockage. I had mine to block up once after running in shallow water.

 

[jackd1023]

Re: Mark 58 - how do I clean the water jacket?

This may be a dumb idea but it happened to me, the hose that connected to the 'pee hole" was clogged on my old one, real simple fix. Darn mud wasps I think

 

[new2mercs]

Re: Mark 58 - how do I clean the water jacket?

Sure wish it could be that easy, but the Mark 58 -- mine at least -- doesn't have a hose to the telltale: The output is directly from the bottom of the block through the lower cowl.

 

[new2mercs]

Re: Mark 58 - how do I clean the water jacket?

For good or ill, I hit the exhaust manifold cover bolts with the oxyacetylene torch. I ended breaking two of them but can't say whether I would've broken more or fewer without it. It did occur to me that I may have annealed them now and might bust 'em all next time. On the other hand, the two that broke just sheared off the heads: My first approach will be to MIG weld bolts onto the exposed bolt-ends... they've been soaking in Liquid Wrench for 48 hours now. If they shear again, then time for drilling and extractors.

I do have another question now though: When I pulled my exhaust manifold cover, I noticed that the underlying plate (divider plate?) was sorta... sprung. There were several gaps apparent as visible in the attached pic. Is this anything to be concerned about, or is it expected?

 

[Aqualift]

Re: Mark 58 - how do I clean the water jacket?

On my 68 Merc 500, I ended up busting 6 bolts trying to get the exhaust cover off. I guess you did better than me. I drilled them out and retapped as an extractor failed. My baffle plate was thicker than yours, so it was flat and not 'sprung' like you mentioned. The thinner plate on yours might be normal. Maybe another Mark58 owner can comment on that.

What did the passageways look like? Did you find any blockages or corrosion. On mine, I had some bad corrosion and sand.

 

[new2mercs]

Re: Mark 58 - how do I clean the water jacket?

Definitely blockage though I don't think in the main passages... that's why I pulled the covers in the first place: no pee!

I don't see anything too terrible in the way of corrosion, but wouldn't expect much as this is a freshwater engine (if the sellers are to be believed). Assuming the story is more-or-less true, there might be some residual radioactivity from the Hanford Reach of the Columbia, but it's never seen saltwater. On the other hand, this motor was supposedly running when it was pulled off a boat either five or seven years ago, depending on the brother telling the story, yet it had a magneto pilot adapter from a six-cylinder and didn't engage the throttle lever on the carbs. Odd that it ran so well in that condition, huh?

Picture attached of the pee-hole blockage.

Hey, just noticed your user name, Aqualift! I'm prepping this motor to go on my '59 Fireflite... much more appropriate in both look and vintage than the '61 Evinrude that's currently hanging off the transom.

 

[Aqualift]

Re: Mark 58 - how do I clean the water jacket?

The passages in that photo look good. A similar one on mine was plugged solid for several inches. The 59 FireFlite is one cool and very unique looking boat.

 

[new2mercs]

Re: Mark 58 - how do I clean the water jacket?

It's certainly fun to drive around... .

Welding didn't do anything for me other than shear off the bolts flush with the block. Currently taking a break from running holes for the Alden "Drill-Out" extractor... .

(Good thing for the break too, as the four-year-old just got out of bed. Little bugger -- this is Papa's two-hour window to get something done!)

 

[new2mercs]

Re: Mark 58 - how do I clean the water jacket?

Alright.

Busted my "Drill-out" and a left-handed drillbit. Luckily I was able to get the remnants out and not leave chunks of HSS inside the bolt to deal with. Time to quit for the night.

Anyone have hints on getting bolts out of the block without overdrilling and installing Helicoils?

 

[Laddies]

Re: Mark 58 - how do I clean the water jacket?

Try to drill a pilot hole all the way thru the broken bolt to start with, 2 reasons it will give you the ability to get penetrating oil to the other end of the bolt and when using a fluted easy out if you beak it and can't get the broken stub out you can drive it in, in some cases. In your case you can now get to the inside of the exhaust cavity and heat and peen the raised part of the casting around the broken part of the bolt and in some cases that will help loosen the bolt. Let everything cool down just before you try to break the bolt loose, heat the casting on the side of the area of the threads.