Clean an outboard cylinder?

[SailBobSquarePants]

My Mariner 3.3 2 stroke outboard developed a bit of rust around the piston rings, and consequently decided to seize last weekend. It had been stored in a shed after flushing with fresh water, but I did take it off the boat quite late in the season - lesson learned.

I removed the sparkplug, dosed it a few times with WD40, and managed to get the piston free. Using the flywheel bolt, I can move the piston completely up and down in the cylinder - however the flywheel itself will not rotate a full revolution - just back and forth over perhaps 70 degrees of arc, during which time the piston rises, and then falls when the flywheel is reversed. I am guessing that is normal, and there is nothing more I need to do to unsieze the engine?

Secondly, when I look into the cylinder I can see carbon deposits on the piston, and there is just some general muck and junk in there. The sparkplug itself was fouled with something reddish. What I would like to do is clean out the cylinder before I replace the (new) sparkplug - someone recommended Seafoam, but that seems to only be available in the US. For us UK dwellers, does anyone have any suggestions? Diesel as a cleaner, perhaps?

Many thanks!

 

[Heckler]

My Mariner 3.3 2 stroke outboard developed a bit of rust around the piston rings, and consequently decided to seize last weekend. It had been stored in a shed after flushing with fresh water, but I did take it off the boat quite late in the season - lesson learned.

I removed the sparkplug, dosed it a few times with WD40, and managed to get the piston free. Using the flywheel bolt, I can move the piston completely up and down in the cylinder - however the flywheel itself will not rotate a full revolution - just back and forth over perhaps 70 degrees of arc, during which time the piston rises, and then falls when the flywheel is reversed. I am guessing that is normal, and there is nothing more I need to do to unsieze the engine?

Secondly, when I look into the cylinder I can see carbon deposits on the piston, and there is just some general muck and junk in there. The sparkplug itself was fouled with something reddish. What I would like to do is clean out the cylinder before I replace the (new) sparkplug - someone recommended Seafoam, but that seems to only be available in the US. For us UK dwellers, does anyone have any suggestions? Diesel as a cleaner, perhaps?

Many thanks!

If it wont turn over it is still seized, red stuff = rust, are you sure you havent had water in it?
You need to keep worrying it till it turns over 360 degrees, its not only the cylinder and piston that can seize, big end rollers, main bearings etc. If it was me I would strip the lot down
Stu

 

[vyv_cox]

Secondly, when I look into the cylinder I can see carbon deposits on the piston, and there is just some general muck and junk in there. The sparkplug itself was fouled with something reddish. What I would like to do is clean out the cylinder before I replace the (new) sparkplug - someone recommended Seafoam, but that seems to only be available in the US. For us UK dwellers, does anyone have any suggestions? Diesel as a cleaner, perhaps?

More snake oil. These products are aimed squarely at people who don't have the ability to take the engine apart. A small outboard is a doddle to work on and you can download the workshop manual for yours free of charge. Strip it down and clean it up properly. You will learn how to do it, enhance your standing in the yacht club(!) and make a proper job of it.

You could just take the head off, which will perhaps 70% fix it, but it seems likely that the rings are going to be rusty and carboned up. Go very carefully with the piston rings, which are brittle, especially when fitting the piston back in the bore.

As Stu says, if water has been inside for a while it may have suffered more. Another reason for taking the cylinder off, so you can see inside the crankcase.

 

[VicS]

I agree. As Vyv says the only effective way of sorting it out is to dismantle and inspect pistons , rings bores and bearings. Replace any parts damaged beyond further use. Clean and oil before reassembly.

Hopefully not beyond economic repair.

In future after the last use not only flush the salt out of the cooling system ( you should be doing that after every use ) but use fogging oil to thoroughly lubricate the engine's insides before storing upright in a dry corner of the garage.

( I use 2 stroke oil in a trigger spray bottle sprayed gently into the air intake until the engine dies.)

Seafoam, popular in the USA as it may be, is not likely to be the solution in this case.

 

[SailBobSquarePants]

Thanks guys!

After reading the first reply, I tentatively exerted a tad more force on the flywheel nut, and lo and behold it moved all the way in a 360 circle. So, from an un-seized perspective, it appears to work.

However, I do catch all of your comments that the best thing to do is tear her down and clean her out. A bit difficult when you don't own a torque wrench, or piston ring pullers, or...well, anything that is specialized.

I did download the repair manual (which did say "don't even attempt a re-assembly with out a torque wrench!") and I'm having a look. I'm really not sure that I'm up for a disassembly myself, due to lack of time and tools...

I suppose that the real danger is that if I don't clean it out the rusty piston will score the cylinder liner, I'll lose compression, have difficulty starting, and in general just be ****e. So perhaps if I can't swing it it's time to farm it out...

 

[Cymrogwyllt]

one way to look at it is that you have nothing to lose by having a go. A broken one is worth next to nothing. Consider the possible part costs of course.

 

[Heckler]

Thanks guys!

After reading the first reply, I tentatively exerted a tad more force on the flywheel nut, and lo and behold it moved all the way in a 360 circle. So, from an un-seized perspective, it appears to work.

However, I do catch all of your comments that the best thing to do is tear her down and clean her out. A bit difficult when you don't own a torque wrench, or piston ring pullers, or...well, anything that is specialized.

I did download the repair manual (which did say "don't even attempt a re-assembly with out a torque wrench!") and I'm having a look. I'm really not sure that I'm up for a disassembly myself, due to lack of time and tools...

I suppose that the real danger is that if I don't clean it out the rusty piston will score the cylinder liner, I'll lose compression, have difficulty starting, and in general just be ****e. So perhaps if I can't swing it it's time to farm it out...

If its turning over now, keep squirting WD40 in to the plug hole, turn it over, and over and over, you get the picture!
Then empty it and put some light oil in (two stroke will be fine) and do the same. Then clean it out with some more WD40 or petrol. Keep turning over. Then have a go at starting it! Might be an idea to clean the carb bowl out whilst you are at it.
Stu

 

[Channel Sailor]

it is a simple motor, at least just get the head off and look inside properly.

 

[steve28]

in a way i disagree, i would leave the head alone, better to take the bottom off and pull the piston out, change the ring (about 14 pounds), clean and reassemble. If the rust particles are allowed to go up and down the bore will get scored up in no time.


steve

 

[Fantasie 19]

Thanks guys!

After reading the first reply, I tentatively exerted a tad more force on the flywheel nut, and lo and behold it moved all the way in a 360 circle. So, from an un-seized perspective, it appears to work.

However, I do catch all of your comments that the best thing to do is tear her down and clean her out. A bit difficult when you don't own a torque wrench, or piston ring pullers, or...well, anything that is specialized.

I did download the repair manual (which did say "don't even attempt a re-assembly with out a torque wrench!") and I'm having a look. I'm really not sure that I'm up for a disassembly myself, due to lack of time and tools...

I suppose that the real danger is that if I don't clean it out the rusty piston will score the cylinder liner, I'll lose compression, have difficulty starting, and in general just be ****e. So perhaps if I can't swing it it's time to farm it out...

Next time you're down near Chi you could have a word with Bill at Home Marine in Emsworth Yacht Harbour - very reasonable servicing prices, nice bloke, very helpful, and even more knowledgeable... he'll tell you whether it's worth fixing or not....