Mariner 5 hp 2 stroke seized solid

[andymach23]

After sitting for the winter, I tried to turn over my 5 hp Mariner 1cyl 2-stroke and it is siezed solid. The pull cord won't move at all. The motor has had salt water use as a kicker. It is never flushed during the season. I just warm it up at the dock, so that it's ready to go in an emergency. This is the pattern of use that the engine has had since new in 1999. I appreciate that this is seriously not good for the engine but it isn't possible to flush the motor where I keep my boat.

It ran and started fine up until the end of the season. I'm guessing that salt corrosion has got to it and siezed it up somewhere.

The pull cord is free moving when it is taken off the engine and the start in gear mechanism looks like it is working properly.

I took the cylinder head off and the piston and bore look fine. Tonight I tried to take the lower unit off and it won't budge. I took the two lower bolts off and loosened the shift linkage under the grommet.

The lower unit will twist slightly from side to side but I just can't get it to lower any. I've tried gentle taps with a rubber mallet all round the gear case and it won't budge.

Is the difficulty in dropping the lower unit, related to the seizing maybe?

Any pointers in getting the lower unit off or generally troubleshooting this issue?

Cheers

Andy

 

[Sea Rider]

Re: Mariner 5 hp 2 stroke seized solid

If you remove the pull cord assy and maualy turn flyweel clockwise in neutral, will the flyweel move freely, or it's only stuck when in gear. A very bad issue not to rinse with fresh water after use as this small engine has very small water passages, put a bucket of water under tail to flush with engine on for 5 minutes. Or get the flush adapter attached to engine by water hose, no need to turn engine on as this model does not have a thermostat to open to clean interior head water passages.

Happy Boating

 

[andymach23]

Re: Mariner 5 hp 2 stroke seized solid

Hi

Thanks for the info. If I get it running again the flushing attachment sounds great. I didn't know you could get this.

The engine is stuck when in neutral as well. The flywheel won't turn by hand.

Cheers

Andy

 

[andymach23]

Re: Mariner 5 hp 2 stroke seized solid

Just thought I'd add, when the outboard is in neutral, the prop spins freely. When put in gear the prop cannot be moved.

Just in case this has any bearing on the problem.

Cheers

Andy

 

[bullbat]

Re: Mariner 5 hp 2 stroke seized solid

it could very well be the foot seized up, if it were me i would try to pour some marvals mystery oil in the cylinder and let if sit for a day or so and see if it frees up the top end if that is what is eized ne how

 

[beamin1]

Re: Mariner 5 hp 2 stroke seized solid

it could very well be the foot seized up, if it were me i would try to pour some marvals mystery oil in the cylinder and let if sit for a day or so and see if it frees up the top end if that is what is eized ne how

What he said... Marvels is the only thing I've ever seen free a seized motor....just pull the plugs of and pour some in..

 

[andymach23]

Re: Mariner 5 hp 2 stroke seized solid

Bullbat, what do you mean 'the foot' has siezed up. I'm not familiar wth that term.

I had a look on the marvals mystery oil site and I don't see any evidence of it being available over here in the UK, but there might be something similar. I'll have a look around. Thanks for that.

I got the lower unit off at last. The motor still wont budge with it off.

One problem I have now is that I accidently moved the shift rod when I was carrying the lower unit and I felt the gear box change gear. I thought that it would be a simple matter of pulling or pushing on the shift rod to move through the gears. If I do this on mine there is some up and down slack on the rod but there is no gear changing happening. Any ideas on this guys?

Also is it a bad idea to move the prop by hand 'the wrong way' if the lower unit is in a particular gear?

Cheers for the help so far!

Andy

 

[andymach23]

Could be the crank bearings?

Could be the crank bearings?

I called the local Mainer dealer today to find out the price of a new powerhead. Stupidly expensive compared to the price of a new engine. The tech thought that the crank bearings could have siezed.

Does this sound like it could be it?

If it is my next question is how this could have happened? Is there maybe something up with the lubrication in the motor that could cause this?

Cheers

Andy

 

[andymach23]

Found The Problem, Pictures attached

Found The Problem, Pictures attached

I took the power head off and found that the part where the drive shaft enters the engine to be packed solid with salt. The shaft must normally spin freely in this collar.

I've attached some pictures of the problem.

Is it normal for salt water to be in this area?

There is also black tar like stuff on the collar. I'm thinking that this is from the exhaust.

If I replace this part will the engine be fixed or could there be something else going on?

Any advice on this much appreciated.

Cheers

Andy

 

[saumon]

Re: Found The Problem, Pictures attached

Re: Found The Problem, Pictures attached

You said that the drive shaft don't rotate, but is the crankshaft free now? Can you now turn the flywheel by hand?

If you look where the splines of the driveshaft enter into the crankshaft, does the seals look good?

Because if you answer yes to theses questions, you may be ok by replacing the driveshaft housing. But you'll also have to be sure that the water cooling passage are clear...

If it don't rotate freely and/or salt corrosion enter into the crankcase by the lower seal, you'd be better to simply throw it in the garbage...

 

[andymach23]

Re: Mariner 5 hp 2 stroke seized solid

Yes, the motor is totally free now. The piston is moving beautifully with the slightest touch of the fly wheel. The lower seal looks good so I think the new drive shaft housing might to the trick.

The cooling pasages have some salt present and they are tiny. I'm going to clear these out with a probe and maybe get something that will dissolve salt.

Cheers

Andy