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View Full Version : rookie donzi owner looking for omc engine info



slacker
06-01-2005, 11:04 AM
I recently purchased a '88 20'minx that has the omc kingcobra 350 and am looking for info about this particular(tired) 350.
the boat only has 435 hours on it but 2 of the cyllinders are dead....I am probably just going to do a cheap rebuild on it for now(pistons & valve job if the crank is ok) ......
lookin for comp ratio specs, did these come w/forged pistons? cam info etc etc.....
probably going to build a b&m type blower motor for it over the winter.....
what kind of hp & torque can these omc's handle?
whats a good pitch prop to use on it?
I have a alpha 1 mercruiser in the shop, but don't really want to get into a refit just yet....
thanks in advance for you ideas & info
slacker

RedDog
06-01-2005, 11:48 AM
First - are you sure it is a King Cobra or a regular Cobra? I would think a regular Cobra would be mated to a 350.

If it is a King Cobra it should handle a blower motor to say 650 HP. The Alpha and regular Cobra will explode with a blower's power (so I've been told).

MOP
06-01-2005, 02:41 PM
If you have a bottom shifter OMC they will hold about 350 crank HP which should get you around 60MPH, but if you have the King like Red Dog says go for it.

Phil

slacker
06-02-2005, 06:17 AM
First - are you sure it is a King Cobra or a regular Cobra? I would think a regular Cobra would be mated to a 350.

If it is a King Cobra it should handle a blower motor to say 650 HP. The Alpha and regular Cobra will explode with a blower's power (so I've been told).

just going by the cover on the air cleaner.....
as soon as I get the algae scrubbed off of the outdrive I'll check the serial #'s....
is there a site that lists what serial #'s are what?
what prop should I be using for the stock 350/270hp(yawwwn)?
I have a 20p elete 1 left over from my mercruizer days......
thanks for your help
ya'll seem to have a nice forum going here
slacker

mattyboy
06-02-2005, 06:32 AM
an OMC Minx???? that's the first I have heard of that, wonder if it has to be be at the end of the run of Minx's I would think seeing OMC took over in 88
could it be the last MINX ever made???
what's the hull number on that???

onesubdrvr
06-02-2005, 06:41 AM
just going by the cover on the air cleaner.....
as soon as I get the algae scrubbed off of the outdrive I'll check the serial #'s....
is there a site that lists what serial #'s are what?
what prop should I be using for the stock 350/270hp(yawwwn)?
I have a 20p elete 1 left over from my mercruizer days......
thanks for your help
ya'll seem to have a nice forum going here
slacker
You're 20p elete 1 if hubbed fro Merc won't work as is. Stock prop is a 19p for that engine, Viper,... anyway, I'm running a Turbo I on mine, runs nice.

in 1988, the OMC KingCobra package was the 350, I believe a slightly modified intake, if memory serves me correctly from when I did my rebuild, 280hp? Anyway, the 1988 "KingCobra" out drive was a Cobra outdrive with different gearing (I believe 1.51, vice the standard 1.63). The true King Cobra (big power handlers), didn't come out until early 90's (if memory is correct, 92 or 93)

Just my comments, may be smashed at any time by the older, wiser ones!!

Wayne

gcarter
06-02-2005, 06:57 AM
Yes, tell us the hull number!!!!!

mattyboy
06-02-2005, 08:35 AM
some pics too :)
gcarter do you have any omc powered minxes in your database???

gcarter
06-02-2005, 09:10 AM
some pics too :)
gcarter do you have any omc powered minxes in your database???
Nope, this is something new and different.

RedDog
06-02-2005, 09:13 AM
See attached photo - '90 model OMC King Cobra. Notice the "hump" on top of the drive - that indicates the drive has the cone clutch. Earlier models ('89 - back) of the King Cobra had a flat top and a dog-clutch similar to the Alpha drive. Note - this drive has an aftermarket nose-cone added.

HamrenDan
06-02-2005, 10:57 AM
I just love the wealth of knowledge on this list..

Here is a pic of my outdrive 1990 Z-22. PS this is mated to a 460

slacker
06-02-2005, 04:50 PM
Yes, tell us the hull number!!!!!

I don't have the hull# here at work....will get it tonite & report back to ya.....
no pix yet
it DOES have a flat top....so what kinda power can ya feed a '88 cobra?
thanks
slacker

onesubdrvr
06-02-2005, 05:28 PM
I don't have the hull# here at work....will get it tonite & report back to ya.....
no pix yet
it DOES have a flat top....so what kinda power can ya feed a '88 cobra?
thanks
slacker
Well, I WAS feeding mine 345 (+/-),l won't do that again. Keep in mind, I wasn't using the high HP gear set either (260hp gear set). I'm sure I had additional issues, but, the upper is not rebuildable, and the lower needs a complete rebuild (including gear), if I want to continue to use existing drive.

The drive might handle more, but even though I drive pretty safe and "calm", I want to be able to have some fun now and then, and I think (with my gears), anything over 260, unless driven "Gently" is asking for trouble.

Good news? well, check this out
http://www.marinepartsexpress.com/cobraconversion.htm

I'll probably do this, and the SX drives are MUCH more durable

Wayne

PS, I used to say, no problem, I'll drive it gently, then I hit 60mph, and a wake or 2, WEEEEEE!!!! I WANT MORE!!!

slacker
06-02-2005, 08:26 PM
Well, I WAS feeding mine 345 (+/-),l won't do that again. Keep in mind, I wasn't using the high HP gear set either (260hp gear set). I'm sure I had additional issues, but, the upper is not rebuildable, and the lower needs a complete rebuild (including gear), if I want to continue to use existing drive.

The drive might handle more, but even though I drive pretty safe and "calm", I want to be able to have some fun now and then, and I think (with my gears), anything over 260, unless driven "Gently" is asking for trouble.

Good news? well, check this out
http://www.marinepartsexpress.com/cobraconversion.htm

I'll probably do this, and the SX drives are MUCH more durable

Wayne

PS, I used to say, no problem, I'll drive it gently, then I hit 60mph, and a wake or 2, WEEEEEE!!!! I WANT MORE!!!

yeah that 'I want more' part has cost me a career change & lots o dollars in the dirt car dept....I doan know much about H2O BUT 6OOHP on pavement & dirt is fun
back to my minx
hull # DMRCB155I788
pix when it gets cleaned up
l8r
slacker

slacker
06-02-2005, 08:58 PM
Slacker,

Is that a Testarossa?

wuz told that it is a minx....from lookin thru the archives it's #155.....
I dunno
lookin forward to band-aiding the motor to have compression on all 8 not 6
l8r
slacker

gcarter
06-02-2005, 09:03 PM
Well, it's certainly not one of the very last built, probably seven or eight after this one.
Would Donzi have provided an OMC drive as a "special order"?

gcarter
06-02-2005, 09:09 PM
So this definately isn't one of the very last built. There may have been nine more after this one.
So I'm wondering if Donzi may have supplied an OMC drive as a "special order"? Or maybe it's been re-powered? Could that be?

mattyboy
06-02-2005, 09:11 PM
could it possibly have been an unrigged unsold boat and went with the purchase to OMC and they rigged it???


you mean like this one Poodle

gcarter
06-02-2005, 09:17 PM
OK, I'm wrong, only eight more. Joe Hahml boat is #163!!!!

gcarter
06-02-2005, 09:20 PM
And Jeff Halls is #160.
Maybe Matty is right.

gcarter
06-02-2005, 09:22 PM
That looks nice Matty.
You know, I'm going to re-gel the bottom this summer....I could do it in red and just keep going up.......

Greg K
06-02-2005, 09:31 PM
I recently purchased a '88 20'minx that has the omc kingcobra 350 and am looking for info about this particular(tired) 350.
slacker

Send me a PM or e-mail and I'll be happy to take a look at it for you and see what can be done.

mattyboy
06-02-2005, 09:32 PM
here's another angle well of just the windshield hey that's 2 stainless windshield there ;) that's Joe Wilkes red and white Minx all the way in the back
i agree with Poodle not a repower was done at the factory

gcarter
06-03-2005, 10:43 AM
here's another angle well of just the windshield hey that's 2 stainless windshield there ;) that's Joe Wilkes red and white Minx all the way in the back
i agree with Poodle not a repower was done at the factory
Matty, can you get the hull #'s for these boats?

mattyboy
06-03-2005, 10:55 AM
yeah, if I ever see them again
but it's gonna cost ya :yes: ;)

gcarter
06-03-2005, 12:42 PM
yeah, if I ever see them again
but it's gonna cost ya :yes: ;)
Whadda I hafta do, be nice to you????? :uzi:

mattyboy
06-03-2005, 03:16 PM
don't threaten me :tongue:

I got enuff friends

get yo own damn hull numbers



;)

slacker
06-03-2005, 03:51 PM
Is it all red, gray interior??

yes solid red w/grey interior.....

I purchased the boat from it's 2nd owner who bought it from a former employer w~20hrs on it....

boat wuz originally used as a dinghy for a yacht

I'll see if they have any documentation or other info on it

still wondering what pitch prop I should get for the thing after I get the motor healed up

slacker

Greg K
06-03-2005, 05:27 PM
yes solid red w/grey interior.....

still wondering what pitch prop I should get for the thing after I get the motor healed up

slacker

Slacker...are you also Slacker on LKNFUN ? Get up with me by PM or e-mail and I'll help you out with what you have there.

Greg

mattyboy
06-04-2005, 07:38 AM
well it's not like us nu yorkas aren't a friendly bunch ;)
seriously
george that pic was from like 3 or 4 tears ago, those 2 boats frequent lake george so if I see them up there this year I'll see what I can do for ya

gcarter
06-04-2005, 06:03 PM
Thanks Matty!
I know all you New Yorkers get kind of crusty from being so close together (except MOP).

:)

slacker
06-06-2005, 09:29 PM
First - are you sure it is a King Cobra or a regular Cobra? I would think a regular Cobra would be mated to a 350.

If it is a King Cobra it should handle a blower motor to say 650 HP. The Alpha and regular Cobra will explode with a blower's power (so I've been told).

isn't there a serial # xref out there somewhere?
the out drive ser# is 579215
it has a flat top so I guess it's a cobra not a king......

thanks
slacker

RedDog
06-07-2005, 07:20 AM
isn't there a serial # xref out there somewhere?
the out drive ser# is 579215
it has a flat top so I guess it's a cobra not a king......

thanks
slacker

Maybe I wasn't so clear before. There is the regular Cobra and then 2 versions of the King Cobra. KC with flat top and KC with the hump which has the cone clutch. The KC with the cone clutch went into production in '89 or '90 - possibility in mid-model year.