Powerhead removal

Dobieman · 13 April 2010, 19:35

Hi All
Any tips on removing a powerhead on my Mariner 50hp 4 stroke as i need to get it off to replace the water grommet on the adaptor plate ( see my other thread 'Outboard cooling' )

my workshop manual makes it look very easy :

1. Drain engine oil
2. Remove lower cowlings
3. Disconnect a few bits and bobs- Fuel line, throttle and gear cables, battery leads ect
4. Undo 5 bolts either side and powerhead will lift off.

All seems too easy to me......

A big question is would i be better removing the lower unit first so the driveshaft and gear shifter rod are out the way?

Thanks

Nos4r2 · 13 April 2010, 20:06

Quote:

Originally Posted by Dobieman

Hi All
Any tips on removing a powerhead on my Mariner 50hp 4 stroke as i need to get it off to replace the water grommet on the adaptor plate ( see my other thread 'Outboard cooling' )

my workshop manual makes it look very easy :

1. Drain engine oil
2. Remove lower cowlings
3. Disconnect a few bits and bobs- Fuel line, throttle and gear cables, battery leads ect
4. Undo 5 bolts either side and powerhead will lift off.

All seems too easy to me......

It's not difficult with the right tools.

Quote:

Originally Posted by Dobieman

A big question is would i be better removing the lower unit first so the driveshaft and gear shifter rod are out the way?

Thanks

Yes-it makes it far easier getting the powerhead off but don't forget to put the shift rod back in before you put the powerhead back on...

outboardtech · 14 April 2010, 17:58

Yip It does seem all easy . After pulling the powerhead you then have to pull the adaptor palte off . you have to do this by removing the top mount's and the bottom mounts to pull the midsection off . the midsection HAS TO COME OFF ASWELL . This is not a 5 minute job trust me . Water tube has to come out , better with gearbox off . The adaptor plate lifts up and then you can access the grommet . did you see my photos in last thread

Dobieman · 17 April 2010, 20:15

I removed and checked the thermostat today and it's ok so the only thing left is the grommet.

I'm pulling the powerhead off tomorrow to inspect it, really hope it is the problem as i can then take steps to fix it.

I'll try to take a few photo's and report my progress...

outboardtech · 17 April 2010, 21:32

Good luck , have fun doing it . It is the GROMMET

Dobieman · 18 April 2010, 14:49

Outboardtech - you are spot on, it is the grommet....

The water tube itself is fu=ine and so is the adapter plate, just need a new grommet and the 2 gaskets and she'll be as good as new.
i did not take off the top mounts to get the mid section off, just the lower ones, unbolted the adapter plate and it fell away.

when i put the new grommet in is there anything i can do to stop this happening again? maybe apply a layer of grease between the grommet and plate?

thanks for the advise

Here's a couple of picture's :

outboardtech · 19 April 2010, 14:27

SPOT ON , Well done . you must clean up all that salt corrosion around that adaptor plate . Use abit of corrosion free grease when putting that new seal in . Make sure you put two NEW GASKETS ON THERE BUDDY . It will ONLY bite you back when you put it all back together and you later find WATER IN THE OIL .

GOOD JOB

Dobieman · 19 April 2010, 19:27

got the new gaskets and grommet on order, should be here in a few days.
Dont know how mariner can justify nearly £150 for these 3 bits though...
I'm still really pleased anyway, cant wait to get her back together and running again,

Dobieman · 25 April 2010, 09:34

All sorted now...

Before:

After :

I reckon i'm lucky it didnt overheat and do any real damage...

What happened to today being the hottest day of the year so far? It's raining here at the mo..

Razorbill RIBs · 25 April 2010, 11:12

Great Job

My old 50 4stroke Merc had exactly the same issue just after I sold it (threads about it on here).....never saw mine...was done by a mech with the new owner (not at new owners cost) amazing just how closed up they get!!

Oh and it's raining here too...

Dan

Reloder · 13 June 2010, 21:52

I am having the exact same problem, 1996 50 HP 4 Stroke Mercury. I was on the same path as you when I stumbled onto this. I would have changed the thermostat next as this only happens when I idle down after a long run.

When you say three items, I understand it needs the grommet and adapter plate gasket. What is the second gasket?

About how long did this take you to do? I am fairly mechanically inclined and have rebuilt automotive engines before. I have access to an engine hoist as well.

Are there any other wear issues or preventative maintenance parts in that area that I should change out as well?

I guess at 14 years the entire engine is preventative maintenance.

Dobieman · 14 June 2010, 18:50

The 3 parts are gasket between powerhead and adapter plate, gasket between adapter plate and mid section and the grommet itself.

Have you inspected your thermostat, mine was full of crap but working fine so i just cleaned it up and put it back in,

The job took me approx 5 hours total ( with someone giving me a hand )

Are you doing the impellor whilst the lower unit is off?

It was suprisingly easy to do, i just took my time and took a few photo's to remind me how it went back together.

Also do you have a manual for it, i found that really helpful looking at the exploded views..... ( i got mine on ebay on disc for about £3 i think )

Reloder · 15 June 2010, 04:40

No, I haven't inspected the thermostat but will. I anticipate that this grommet will be the culprit though. The previous owner ran this engine at the mouth of the Columbia River in Oregon, USA. When I changed the impellor, everything looked flushed that could be but there were some salt crystals in the exhaust passages. If saltwater eats away grommets even with religious flushing, it would be prudent to change anyway.

Even if it isn't the problem, I think it will be a nice courtship and looks to be easier than the four-carb adjustment. I know there were a few bikes out there with four carb setups, but on an outboard with a vertical setup it looks like a major PITA. I suppose there are those out there that would prefer this to the newer EFI models.

I do have a factory manual and it makes the job look like a few minutes off and a few back on. I think I will have to take my time as you did and try to look for any additional problems.

I can't believe the pricing either. If you bought this engine from parts it would cost $50,000!

Timestep · 23 October 2011, 15:03

An old thread I know, but it's just happened to me!

I'm confused, why do you need to remove the mid section? Won't the adaptor plate just lift off?

The engine is off. The five bolts are out. The Allen screw has its head drilled off. The two M12 top steering bolts are out. The gear linkage is out. Whatever I do, I cannot separate the adaptor plate. I thought I was an engineer!

Thanks

Dave

johnza · 02 April 2012, 09:40

thanks a bunch guys
a much needed thread
Fixed my 2001 Mercury 60 four stroke thanks to this
My gromet was in a far worse state tho

uncle al · 02 April 2012, 15:15

done loads common fault , unfortunutly the factory not interested i dont know now though as i have been retired just over a year very few qualified for warranty we had to beg , and i believe the factory has got even tighter on warranty now

Timestep · 25 August 2018, 17:05

UPDATE : It was welded together by corrosion and would not part.

I made a case to Mercury in 2012 that it was faulty manufacture, they gave me a brand new engine with full 5 year warranty and fitted it, for half the price of the engine alone. Not bad ?

Dave

sfladgard · 06 September 2018, 23:52

Quote:

Originally Posted by Timestep

UPDATE : It was welded together by corrosion and would not part.

I made a case to Mercury in 2012 that it was faulty manufacture, they gave me a brand new engine with full 5 year warranty and fitted it, for half the price of the engine alone. Not bad ?

Dave

Dave-

thanks for the update. Finally got mine apart but warped the adapter plate in the process. This is getting expensive.

Timestep · 07 September 2018, 06:23

Quote:

Originally Posted by sfladgard

Dave-

thanks for the update. Finally got mine apart but warped the adapter plate in the process. This is getting expensive.

To be honest I would sell it on eBay ? That is what I was going to do, or part it out, the engine and bottom leg is worth a bit. But then Mercury took it away and fitted a new one, I was lucky, but persistent.

Dave

jackweathers223 · 11 March 2019, 12:42

What kind of rv jacks or lifting equipment did you use? Really good job on that work.