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Old 11-06-2013, 02:24 AM   #1
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150v6 reluctant new 'project' - advice/help? :)

Very brief, so I finally finished rebuilding a 17ft Fletcher I've had since 2010, and found a cheap 1979 150v6 engine to put on it.

I did a bit of service work on it before it went on with ignition and carb, waterpump service/overhaul etc, but comp was down on cyl 4 to around 50% of the other 5 cyls. I decided since I didn't know the rest of the engines history to give it a go anyway, and see if it was stuck rings etc. Well after a first run it picked up to around 60 ish psi, but after a second its now totally dead reading all of around 10psi.

So I've gotta pull the powerhead and sort it out.

Main thing I'm wondering is, can anyone recommend me a machine shop in Surrey/SE who is able to bore these old blocks should I need to fit an OS piston in cyl 4?

I also asked on the for sale/wanted section, but am after a rod+piston too as I also noticed that the top cyl above no.4 has some play in the con rod/piston/crank bearings.

Finally I just noticed looking for parts on ebay that merc did a 175v6 2.0 at the same time they did the 150v6. If its all in bits, I'd be interested to see what was necessary to make this a 175?

Thanks for any advice, really could do with some voices of experience on this
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Old 11-06-2013, 10:17 AM   #2
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V6

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Very brief, so I finally finished rebuilding a 17ft Fletcher I've had since 2010, and found a cheap 1979 150v6 engine to put on it.

I did a bit of service work on it before it went on with ignition and carb, waterpump service/overhaul etc, but comp was down on cyl 4 to around 50% of the other 5 cyls. I decided since I didn't know the rest of the engines history to give it a go anyway, and see if it was stuck rings etc. Well after a first run it picked up to around 60 ish psi, but after a second its now totally dead reading all of around 10psi.

So I've gotta pull the powerhead and sort it out.

Main thing I'm wondering is, can anyone recommend me a machine shop in Surrey/SE who is able to bore these old blocks should I need to fit an OS piston in cyl 4?
I also asked on the for sale/wanted section, but am after a rod+piston too as I also noticed that the top cyl above no.4 has some play in the con rod/piston/crank bearings.

Finally I just noticed looking for parts on ebay that merc did a 175v6 2.0 at the same time they did the 150v6. If its all in bits, I'd be interested to see what was necessary to make this a 175?

Thanks for any advice, really could do with some voices of experience on this
The early v6 merc's are chrome lined not sure you can rebore them.
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Old 11-06-2013, 11:10 AM   #3
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Get in touch with pro rig marine at Penton hook marina, Rob will be able to tell you more.
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Old 11-06-2013, 12:56 PM   #4
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New powerhead

Might be an option just to buy an xr2 powerhead that's just been put on the trading post.job done easy fix.
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Old 11-06-2013, 05:23 PM   #5
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XR2 sounds interesting, may be out of my budget, I have no idea what they are worth?
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Old 13-06-2013, 11:16 AM   #6
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Ok going to attempt a fix on this anyway I think. Seems a shame to scrap it, if its salvageable.

I have a general question relating to this engine however. When I did have it out, it averaged fitted to a 17ft Fletcher 1.6 Litres per mile. Or about 3.2 MPG. Ok turns out that was on 5 cyls, 4 adults, and at a max of 46mph (GPS), but I think over propped at 5000 rpm max on an alloy prop. Does all that sound 'reasonable' given the circumstances?
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Old 13-06-2013, 12:04 PM   #7
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Ok going to attempt a fix on this anyway I think. Seems a shame to scrap it, if its salvageable.

I have a general question relating to this engine however. When I did have it out, it averaged fitted to a 17ft Fletcher 1.6 Litres per mile. Or about 3.2 MPG. Ok turns out that was on 5 cyls, 4 adults, and at a max of 46mph (GPS), but I think over propped at 5000 rpm max on an alloy prop. Does all that sound 'reasonable' given the circumstances?
I would get shot of the alloy prop ,really not man enough for a v6 merc you need a stainless steel prop.
If only running on 5 cyls,and still 5000 rpm sounds good only about 700 rpm,s out on full revs , so your prop pitch is properly about right.
Not sure on fuel consumption other will know what it should be if running on all 6 cyls.
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Old 13-06-2013, 03:39 PM   #8
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Ok thats interesting thanks for that. I did wonder at which point alu props would not be the material of choice.

Would be interested to know the thoughts of anyone else too.
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Old 17-06-2013, 12:19 AM   #9
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Pulled the power head off today. Removed the cyl heads too. Its got some corrosion around the water jackets, some quite bad really - nearly makes it out to the outside world, and has in one area, but probably weldable. It didn't have a problem with me running it, still a pain though.

Cyl 4 has slight bore scratches, but oddly seems to have aluminum on the bore walls. I'm guessing that's piston ring land material.

From what I can tell so far will need a piston probably OS, and a hone/bore.

Just looked up penton hook - thanks Renegade. I see its quite close to where I work, so thats handy.

Any suggestions for a gasket set etc would be handy. I bet somewhere people have these lying about from old stock?
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Old 18-06-2013, 12:13 AM   #10
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Does anyone actually do anything with these any more. I keep posting here hoping I'll find an old hand to these?
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Old 18-06-2013, 12:51 PM   #11
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The trouble with an old motor like that is you could spend 2 grand fixing it and would still only be worth £500 tops
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Old 19-06-2013, 12:44 AM   #12
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Yep. Will know more tomorrow when I finally get the crank out... hopefully will be ok. Or i need to find a better powerhead/engine...
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Old 19-06-2013, 12:55 AM   #13
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found this on ebay...http://www.ebay.co.uk/itm/200-hp-Mer...-/251288762310 Are these engines the kind of thing I should go for then? (dont really want XL shaft however) and would prob have to swap mid section/gearbox or something
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Old 19-06-2013, 05:51 AM   #14
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http://merc-racing.com/

Give them a call.
Ask for Nico, they can also resleeve it if needed

If I where you I would rebuild it, nice old school
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Old 19-06-2013, 03:53 PM   #15
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called pro rig marine, not their thing. They just assemble stuff and said to try and call around automotive machine shops.
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Old 19-06-2013, 11:07 PM   #16
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Block totally stripped and assessed as scrap. Too much corrosion/water in the top two cyls (somehow) which has damaged the crank and a few bearings.

Cyl 4 turns out it had no compression as at some point in its life it looks like the piston had some kind of friction against its bores. Rings are not broken just siezed and stuck in bits of 'melted' alu on the piston ring lands. No sign of det however.

Looks like I'll be looking for a new powerhead.
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