Mark 28 issues

[wedgie]

Just getting back to this darkside motor. I got it running a couple years ago, but suspected the crank halves are leaking, so put it aside.

Also, as many of you know, the starter is integral to the hood, so to test run without it, you need to rope start it. When doing so, as I remember, it would often yank back on the rope half way through the pull. hard enough that it would yank the rope out of my hands. I’ve had that happen on a omc 6 horse too. Timing issue ?

My Mercury Mark 28 has 110/112 lbs. Is that acceptable ?

Thanks

[dave-bernard]

not timing issue.
that compression is fine.

[wedgie]

Thanks Dave.

[20mercman]

I have quite a few of the 22 cid. power head motors, and I have yet to have one where the case halves were leaking. I have found crank seals, transfer port covers, fuel pumps, even a very loose reed block retainer bolt that can cause a crank case leak. What lead you to believe you have a case leak? These are real easy to separate the cases, so opening it up would not be much of an issue. A good time to replace the bottom crank seals anyway. As Dave said, this compression is good. Another item to check is the exhaust baffle cover to make sure it has not dried out and is leaking. Exhaust can leak into the water, and water can get into the block if they are leaking. I had a salt water motor that the baffle plate corroded through. These are great motors, and I am sure you will really like it once you get the bugs worked out.

Steve

[garry-in-michigan]

Jerking the rope out of your hand is the characteristic off an over advanced ignition. The start position is usually set at top dead center. Fireing before TDC gives more power at higher speeds but makes the motor want to run backwards at cranking speeds. A racing motor with a fixed timing takes a very strong arm to crank over sucessfully. . . 😆

[jeff-register]

If you suspect someone else having the halves apart they may have missed the o-ring that is part of the case halves. What makes you think they are leaking? Try grounding the mag to the block. Those motors are great at reversing current with the mag. Mine was missing on the top then the bottom screwey! Bonded the mag & it ran great. Look at the points for overheating, mine turned gold they were so hot from the reverse!!

[wedgie]

I’m almost positive it had been apart before I got it, so that’s why I thought it may be leaking . The p/o stripped the outside of the power head with paint remover too. I will pull the flywheel and have a look at the points again though it hadn’t had much run time on it since I replaced the coils. It’s been so long now that I don’t remember what they looked like . I must’ve cleaned them at that time but don’t recall. I have the service manual now, so I will read up on it this time around.

I could get it to start but the rpm’s wouldn’t come up. The carb was clean and set up properly as far as I knew at the time. I have learned a few things since I did this motor so maybe if I go back in and check all the areas Mercman has listed this weekend I’ll spot something I’ve missed 😉

So, having the throttle cranked wide open on this hard to start motor would cause it to pull back?
Since I ruined my rotator cuff a few years back, this is an accurate depiction of my arm strength. 😆

But once I get it started 😉 !!

[wedgie]

Video from a few years ago

http://vid635.photobucket.com/albums/uu … -00003.mp4

[billw]

I start them with the top on. Once it’s warm, I take the cover off. Yes, while it’s running. Yeah, it rubs a bit but no worries. It won’t get jammed or anything.

Long live American manufacturing!

[20mercman]

I was going to post this before, but my post ended up getting deleted, and I forgot to add this when I retyped it. As Jeff pointed out, there is an "O" ring that goes around one of the bottom crankcase bolts that has to be in place. This should stand proud of the face of the case in order for it to seal properly. It is something that can be easily left out if not aware of it.

Steve

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