Powerhead manual - Mariner 100 4cyl 1996

[steve-ribnet]

Hello, hoping some Mariner guru can help out

-I'm looking for the powerhead service section for my 1996 (BEL) Mariner 100HP 4 cyl 2-stroke outboard. I have serious piston issues and am looking to rebuild the powerhead.

this is not the usual request for a common service manual - I have this - part 90-13645--2 Mariner 70-75-80-90-100-115, but my version and all the online PDF versions I have found are all missing the crucial section 4B - powerhead 4 cylinder model!

I have tried the boatinfo.no, the list kindly maintained by 'under the thumb' on this forum, and the first 10 pages on Google, but they too are all missing section 4B!

I can follow the 3 cyl instructions up to a point, but need torque figures, tightening sequences, clearences, tolerances etc specific to the 4 cylinder.

Any help greatly appreciated.

Many thanks
Steve

[9D280]

It's 3 am eternal right now but that sounds like my Clymer might cover it. Gimme a couple of days to find it/reply. ......

[steve-ribnet]

you are very kind sir, thankyou for your time.

I'm wondering whether repair is possible/economical.
Looking through exhaust port, the cylinder liner / sleeve has slipped down 10-20mm on #1 cylinder. It appears the piston rings advanced past the liner lip and then became stuck, taking the edges of the crown off #1 piston. #4 piston shows some wear /material transfer on the side too. Engine still spins freely to a point, but the conrod big end bearing shell catches on the bottom of the slipped liner.

Root cause appears to be incorrect timing (retaining nut on timing arm adjustment came loose) followed by lugging the engine under heavy load for a full day being a boat taxi.

[paintman]

If the liner has moved then it may be a fit issue. If it's basically a pressed fit parallel sleeve relying on the grip of the surrounding metal then a new one may do the same if the surrounding metal is damaged.
The best cure is likely to be a top hat liner - common problem in LR V8 engines, how it's done here:

https://www.youtube.com/watch?v=xx6_NZG18wY

but the question would be their availability for that engine and the costing of the whole job.
Quick google produces these: Welcome to Westwood Cylinder Liners

[phantom 19]

You'd also have employ a magician to fit a top hat liner to a four cylinder merc/ mariner!

[paintman]

Doesn't sound very hopeful then. If it's moved once then it's likely to happen again.
Any other way of locking it into position if a top hat isn't an option?
Possible to press the liner back into place then see what happens?

[Nightfisher]

Do you know the Engine Serial Number?

[steve-ribnet]

Originally Posted by Nightfisher

Do you know the Engine Serial Number?

Thanks all,
serial 096094xx (Belgium)

yes top hat liner won't work - no cylinder head on these to remove! The 'head' is cast as part of the block. The block separates at the crankshaft.
The liners are not plain liners - they have the inlet/exhaust ports.

I now have the engine apart - #1 sleeve has slipped 10mm. Big End case has struck the bottom of the sleeve, marring the liner rim at the base, but has not been damaged itself.

#1 piston crown chipped off at level of 1st piston ring - the chip stuck to the top of the cylinder and didn't do any further damage.

#4 piston shows some metal transfer onto the piston sides and light scratching on the cylinder/liner walls

The other cyls and pistons all look ok - still some honing crosshatch visible on them.

#3 piston doesn't match the others - different marking layout (raised as opposed to etched) and shot-peened crown vs plain crown. I imagine this has been replaced at some stage previously

I'll take some photos at some stage - it's quite interesting to see the guts of one of these

My jobs list is looking like:
* Replacing the sleeve/liner of #1 cylinder
* replacing #1 piston with standard size
* re-boring #4 cylinder and replacing with oversized piston (2 oversize increments are available)

I read on American forums it is quite common to 'pin' the liners to the block if they have slipped. (seems popular with landrover V8s too!)http://www.landroverresource.com/doc...g_V8_Liner.pdf I will give this a go on #1 cyl for sure, and perhaps others.

I'm now looking for machine shops in Glasgow /west Scotland area that could perhaps remove the #1 liner by liquid nitrogen/heat or machining, and press-fit/freeze fit new liner. I have seen them being fitted to a new engine on youtube - easy when you have the right kit!

Might be uneconomical repair after parts and labour - money better spent perhaps on new engine, and sell other parts for spares (the rest of the engine is great)

[9D280]

When I rebuilt the Clamshell I used a place called Blane Precision Engineering. They specialise in that sort of repair and blind bored my 3 trashed cyls.

56.03730, -4.397053 into your favourite mapping program to find them.


Other way of looking at "uneconomical" is I reckon I spent £1200 to get me an "as new" (ignoring the paint job!) Clamshell. I could have spent that on a "used" engine with a non guaranteed history. I went for "known" as the rebuild essentially gave me a new engine. Granted I didn't need to re -line mine so your numbers may work out differently.

[paintman]

Originally Posted by steve-ribnet;695852[FONT=Calibri

][/FONT]
yes top hat liner won't work - no cylinder head on these to remove! The 'head' is cast as part of the block. The block separates at the crankshaft.

Ah. That answers that one!

Originally Posted by steve-ribnet

I read on American forums it is quite common to 'pin' the liners to the block if they have slipped. (seems popular with landrover V8s too!)http://www.landroverresource.com/doc...g_V8_Liner.pdf I will give this a go on #1 cyl for sure, and perhaps others.

Interesting. I knew about pinning liners but not seen that before.

[steve-ribnet]

Originally Posted by 9D280

When I rebuilt the Clamshell I used a place called Blane Precision Engineering. They specialise in that sort of repair and blind bored my 3 trashed cyls.

56.03730, -4.397053 into your favourite mapping program to find them.


Other way of looking at "uneconomical" is I reckon I spent £1200 to get me an "as new" (ignoring the paint job!) Clamshell. I could have spent that on a "used" engine with a non guaranteed history. I went for "known" as the rebuild essentially gave me a new engine. Granted I didn't need to re -line mine so your numbers may work out differently.

Ill look them out, thanks also for the estimate - good to have a ballpark.

[Nightfisher]

Try iBoats in their Mariner repairs section. It not already there, and you join, there are some brilliant mechanics that can either tell you or point you to the site that will. Good Luck

[9D280]

Originally Posted by steve-ribnet

Ill look them out, thanks also for the estimate - good to have a ballpark.

They are local and did come reccomended to me.

It was also the best part of 5 years ago now, so expect a few % up!

[uncle al]

Steve if you do a rebuild, you will need to replace all the big end bolts.otherwise all your hard work will/could be for nothing.