This Boat Motor Has Zero Compression

This Boat Motor Has Zero Compression | Here's Why

Рет қаралды 4,164

3 ай бұрын

I have a Mercury 135hp motor that didn't start. After a few tests, I discovered the three starboard cylinders had zero compression, while the three port side cylinders had normal compression. I did a tear down of the motor and discovered the cause.
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Пікірлер: 33

@hunterb1215 3 ай бұрын

Make sure your water pump is working properly . Could also be an air leak, creating a lean condition. Make sure you find out why all three pistons failed before you put the engine back together, or it will happen again. Hopefully, this helps .

@GoMidwestFishing 2 ай бұрын

Yes, I really don't want the same thing happening again, so I will check everything over. Especially the cooling system. Many people mentioned overheating.

@dougtaylor7724 3 ай бұрын

That thing has run marginally hot for a while. The pistons get hot at the exhaust side and it pushes it over to the transfer port side and makes the lands start dragging and sticks the rings. Your seal ring on crank has always been broken more than likely. Check to see if the block has a groove. If not, they broke the ring when motor was assembled At Mercury. I’ve seen about 20 or so of those. Put a water pump kit in it, make sure the poppet plastic seat is still in place. Sometimes they move and the water doesn’t flow. But you have massive water pressure. That will make one get hot and pop. Replace your check valve that lubes the top bearing. Probably has one on bottom main and one on top. Check your reeds. That will get water in cylinder. Replace the two thermostats also. Did you have any loose bolts when you took it apart?

@GoMidwestFishing 2 ай бұрын

Wow, thanks for all that info. It is really helpful. All the bolts were tight. The motor was really clean and all the gaskets looked new. It looked to me like someone had recently done some work on the motor. I bought it off facebook in this condition. The guy I got it from bought it as a project boat, but didn't have time to work on it, so he sold it to me. He said it had low compression on one cylinder. That's all the info I know about it. I will check all the things you mentioned. Thanks again for your knowledge.

@dougtaylor7724 2 ай бұрын

If the pistons are oversized be sure to mic the cylinders top to bottom. Sometimes you get a bore job and the cylinder is tapered at the bottom. If it’s a little tight the will seize at the bottom of piston first. Make sure you find out what went wrong before you build it. You do not want to repeat a failure.

@sourmashy1 2 ай бұрын

From my 2 stroke experience, the crank seal, likely the cause. A leak there will cause a lean condition, the faster the motor spins the more air it pulls in.

@markglabinski526 3 ай бұрын

This was really interesting. Thanks!

@corey2one 19 күн бұрын

I wish I could add a picture. I have a 1996 150 that looks identical to yours. I was out the river recently and suddenly lost power. Mechanics are all booked. Decided to start looking at the obvious. Opened up the cyclinder head and good lord. I can’t afford to replace the motor so I too am about to order a rebuild kit. But I also don’t know the full cause. I do know I contributed by putting in premium. Apparently that’s a no-no with these motors. One of the piston rings was broken to pieces, all gray/burnt. Without a mechanic, idk if there’s an oil issue, cooling issue, or if higher octane is capable of such damage. So far I seem to be the only girl trying to figure this out on here…I don’t think the odds are in my favor 😂 But either way, I have no boat so what the hell. Might as well try. I hope to see more videos of where you’re at with yours, thanks for the great footage.

@JohnAmes 3 ай бұрын

Some great information my friend

@WesLovelace 3 ай бұрын

The crank and the rollers looked like they were affected by corrosion ...You sure there isn't a crack on the starboard side....The blow by was obviously caused by the sticking rings!!😎

@GoMidwestFishing 2 ай бұрын

The corrosion was very concerning. I will have to look closely into that. I had a specialist do the machine work on the block. So far he says its all good. I really don't want to repeat the same problems it already had.

@robertdoyen5434 3 ай бұрын

This is a very interesting video thanks for sharing your experience with us.

@GoMidwestFishing 2 ай бұрын

Hi Robert. All these short videos on this motor are just part of the process. I can't wait to release the main video showing the transformation from start to finish. That's assuming it actually runs when I am done with it. Its been a huge learning experience!

@f.acatfish9077 3 ай бұрын

I thought you said you are not a boat mechanic, but you are doing great job, as always awesome video my Man!

@GoMidwestFishing 2 ай бұрын

I'm not a boat mechanic, but I play one on KZfaq! I figure by the time I'm done with this motor, I can call myself an amateur mechanic. Thank goodness for youtube, its my go to source when I can't figure something out.

@JonGunnerOutdoors 3 ай бұрын

It is fun tearing into a engine and diagnosing the issues.

@GoMidwestFishing 2 ай бұрын

Its been a big learning experience!

@garyradtke3252 3 ай бұрын

Even the one you called good is scored!

@GoMidwestFishing 2 ай бұрын

It really makes me wonder what the person before me did to this motor. The block just got bored and honed, and all new pistons are on the way. Lets hope it works better this time. Thanks for watching.

@jamuherbal 2 ай бұрын

Hello friend good morning ❤❤❤👍👍👍👍🌹🌹🌹🌹👋👋👋👋

@HuntingFarmerOfficial 3 ай бұрын

Ouch! That’s not good! Looking forward to you getting it purring 👍

@GoMidwestFishing 2 ай бұрын

Taking it apart was the easy part. As long as I don't have any leftover bolts when I get it back together, it should be OK. Thanks Dave!

@lewisbolman7862 3 ай бұрын

Stuck rings may get loose with power tune, follow instructions, some times I let it soak over night.

@garyradtke3252 3 ай бұрын

Aint no magic in a bottle that will free up stuck rings from scoring or that will fix the piston and cyl wall damage.

@lewisbolman7862 3 ай бұрын

On more than one one occasion was was able to free up rings on some outboards that had lower than usual compression, no it won't fix scored cylinders, Jesus use your brain, I brought comps up from 30 to 80. Which I thought was fantastic. When the plugs come out with crud packed on em , it tells me , crappy oil usage or lack of maintenance, so I try before I have to tear into em., did you notice I said " may"....

@wishniwasfishn813 3 ай бұрын

Just subscribed!

@GoMidwestFishing 2 ай бұрын

Welcome aboard! I can tell by your channel name that you like fishing..

@ericvogel1126 3 ай бұрын

Looks like it got badly overheated.

@GoMidwestFishing 2 ай бұрын

Thanks for the info. I will have to make sure all the cooling lines are working properly when reassembling it.

@yarrdayarrdayarrda 3 ай бұрын

That material on the cylinders is piston skirt. Coolant issue. Or oil injectors if it's an injected 2 stroke engine.

@GoMidwestFishing 2 ай бұрын

Thanks for the info. It is not oil injected, so probably a coolant issue then. I will look into the cooling system.

@nnglenn 3 ай бұрын

Looks like you overheated it!

@GoMidwestFishing 2 ай бұрын

Thanks for the info. A few people mentioned overheating. It's starting to look like that may be the problem. I got the motor like this, so I'm not sure of its history.