OMC King Cobra care and feeding

KeithKris

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Nov 27, 2017
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Long story short: I have a twin engine boat with two the rare cone clutch outdrives. I tried my best to do my research before buying, but failed in my identification of this unit. I couldn't get a local mechanic to return my calls for an inspection, and surveyors wanted more than half of what I paid for the boat (not much) just to take a look. All that is behind me at this point. I have the boat and want to get the most use out of it possible until it comes time to junk/donate/repower it. I've posted on another forum, but some Googling led me here. It seems like there might be some users here with a good amount of experience and wisdom regarding these drives (I could use both.) Serial number 574APEPWS. I think the good news if there is any is that I have 5.7s, which seem to be easier to locate parts for. Here's an album with photos of the drive and engine.

https://imgur.com/a/7Bq62

Over the summer, I lost an impeller. I had the marina replace it. I think they're well meaning, but inexperienced with these units. The drive ran, but would overheat often, settling into the 200-220 range before it leveled out. Eventually I determined it was taking in air. I think they installed a standard Cobra housing instead of the one meant for the King. I rigged a 12v Harbor Freight special pump from the AC water intake to the engine to get by and enjoyed the fall. The engine seemed to run well enough with this setup.

It sounds like the easiest path for these drives is to replace the pump with a crankshaft mounted water pump. I'll do that while she's in storage for the winter. It sounds like some have gone with through hull water pickups while some have removed the impeller and had the pump pull water through the outdrive. I'm thinking the through hull option is superior in every way except for the fact that you have to punch a hole in the boat. Is this a fair assessment? Am I going to chew up impellers if I try to use the existing plumbing?

Beyond that, what is best practice to keep my drives in the best possible condition? Obviously I will change the oil and lubricate everything that is easily accessible. I've been hesitant to remove the drives for inspection as it sounds like the seal kits would be difficult to find. Could I possibly use sheet gasket material to cut my own seals, or is there more to it than that?
 

Lou C

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Nov 10, 2002
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11,798
I believe the KC impeller units are available at Crowley Marine. Id pick up a few kits and do it yourself. We can walk you thru it; not rocket science!
 

KeithKris

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I believe the KC impeller units are available at Crowley Marine. Id pick up a few kits and do it yourself. We can walk you thru it; not rocket science!


I appreciate it! I think you replied to my post on that other site. Unfortunately it looks like it is not available unless I'm looking in the wrong place. This is where I looked. I believe I need parts 15, 16, 18, and 20, with 20 no longer available.

http://www.crowleymarine.com/johnson-evinrude/parts/55869.cfm

If that's not right, please let me know.

I can find kits on eBay, but they're selling for close to the $150 or so it would cost me to buy a crankshaft pump. Seems like I'm just kicking the can down the road that way.
 

Lou C

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http://www.crowleymarine.com/johnson...arts/55869.cfm

​As long as your housing is OK you need the water pump repair kit #13 and the o ring gasket for the housing #18. Actually I'd buy at least 2 for each engine while they are available. This is an easy job. It takes me about 15 min on mine.

​I don't think the housing for the standard Cobra would even fit on yours, but if you need a new housing and can't find one, try Sea Way Marine in Washington State, they have a stockpile of obsolete OMC parts.
 
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KeithKris

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http://www.crowleymarine.com/johnson...arts/55869.cfm

​As long as your housing is OK you need the water pump repair kit #13 and the o ring gasket for the housing #18. Actually I'd buy at least 2 for each engine while they are available. This is an easy job. It takes me about 15 min on mine.

​I don't think the housing for the standard Cobra would even fit on yours, but if you need a new housing and can't find one, try Sea Way Marine in Washington State, they have a stockpile of obsolete OMC parts.


The housing looks melted where the liner shifted inside. I can say that the standard cobra housing does fit because I bought one before I realized I had a cone clutch. It looks identical to the housing the Marina installed, and has the vent tube on the opposite side from the one on the other drive. It fits just fine, but I read that it won't work for some reason (Not sure why? So much of this stuff seems like legend and hearsay :))
 

HT32BSX115

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Joined
Dec 8, 2005
Messages
10,083
Long story short: I have a twin engine boat with two the rare cone clutch outdrives. I tried my best to do my research before buying, but failed in my identification of this unit. I couldn't get a local mechanic to return my calls for an inspection, and surveyors wanted more than half of what I paid for the boat (not much) just to take a look. All that is behind me at this point. I have the boat and want to get the most use out of it possible until it comes time to junk/donate/repower it. I've posted on another forum, but some Googling led me here. It seems like there might be some users here with a good amount of experience and wisdom regarding these drives (I could use both.)
Howdy Keith,
Welcome aboard!

Well, a little search at http://epc.brp.com yielded OMC #0986997 (obsolete) replaced by OMC #3854661
Available at many aftermarket marine parts distributors or Sierra 18-3469 available right here on iBoats.

18-3469_0.jpg


It was not very long ago that the raw water pump impellers for the cone-clutch OMC (interim) drives were only available as new (old stock) and people were charging a lot for them! They're still charging a LOT but at least you can get them again!

Serial number 574APEPWS. I think the good news if there is any is that I have 5.7s, which seem to be easier to locate parts for. Here's an album with photos of the drive and engine.
It's not just "good news" It's great news because you have standard carburetors and most or all of your ignition parts are still available!

If you "break" a drive however, there may be internal parts that will have to be cannibalized from a used drive.

I will suggest that you not try to use a dog-clutch raw water pump kit on it. I don't why they don't "fit".........But they evidently don't or there wouldn't be a specific kit for your model.


Regards,

Rick

By the way, you don't need that housing unless it's damaged in some way. If it is, you'll probably need to "scrounge" a used one....
 
Last edited:

KeithKris

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Nov 27, 2017
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Howdy Keith,
Welcome aboard!

Well, a little search at http://epc.brp.com yielded OMC #0986997 (obsolete) replaced by OMC #3854661
Available at many aftermarket marine parts distributors or Sierra 18-3469 available right here on iBoats.

18-3469_0.jpg


It was not very long ago that the raw water pump impellers for the cone-clutch OMC (interim) drives were only available as new (old stock) and people were charging a lot for them! They're still charging a LOT but at least you can get them again!

It's not just "good news" It's great news because you have standard carburetors and most or all of your ignition parts are still available!

If you "break" a drive however, there may be internal parts that will have to be cannibalized from a used drive.

I will suggest that you not try to use a dog-clutch raw water pump kit on it. I don't why they don't "fit".........But they evidently don't or there wouldn't be a specific kit for your model.


Regards,

Rick

By the way, you don't need that housing unless it's damaged in some way. If it is, you'll probably need to "scrounge" a used one....


Hearing that is a big relief. I feel a little less "up the creek" at this point. That repair kit doesn't include the actual housing still though, and the I think the housing installed on the bad drive is the one for the standard Cobra. I need to get my hands on the correct one first. That rebuild kit is about the same cost as a Johnson crankshaft mounted raw water pump. To me it seems like switching means I can use a more common impeller and it would be easily accessible when I'm in the water.

That brp site is handy! I was aware of crowley and the Sierra catalog, but had not seen that one.

I'm still wondering about pulling the drive off. It would be nice to inspect the U joints and whatnot, but I'm concerned that I won't be able to get gaskets to put it back on. I'm not sure if trying to make a gasket is a bad idea or not.
 

HT32BSX115

Supreme Mariner
Joined
Dec 8, 2005
Messages
10,083
The transom service kit for a Dog-Clutch does require a gasket.....my previously installed 460 (Dog-Clutch) King Kobra used a gasket..... I could be wrong but I think the Cone Clutch Cobra did not use a gasket between the drive and transom mount, but did use 1 or 2 O-rings.... In any case, you could certainly make a gasket if required.

You absolutely should pull both drives too, if for no other reason than to check alignment. The bellows is (although expensive) is still available at various boat parts places....

The engine mounted raw water pumps are not cheap but will work well and you may have to install thru-hull raw water pick-ups......

However, I would find a used housing for the existing pump.......I think you'd be better off spending as little money on those drives as you can, and if the boat is REALLY nice and you want to keep it, start looking for replacement Mercruiser or Volvo transom mounts and drives for an eventual replacement. On a big boat with twins, I would use Bravo III or Volvo DUO-Prop drives. Not cheap but REALLY a performance upgrade from single prop drives....

A little over 10 years ago, I removed an 87 460 King Kobra (single prop) engine/drive and replaced with a 97 Mercruiser 454 Bravo III. Although the HP and torque were nearly identical across the board, the performance difference was spectacular due to the dual contra-rotating props!

As long as your drives are not damaged or severely corroded, they're still quite valuable. (because there's other people out there that will want to replace drives in the future....)
 

HT32BSX115

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Joined
Dec 8, 2005
Messages
10,083
Hello all, 19 yr boat owner, new to the forum. I own a Seaswirl Spyder 208, it has the OMC King Cobra 454 (7.4L). I bought this boat from my brother in law in 1999 and he was the original owner since new in 1992. Despite the bad press I’ve read about, this boat has been completely trouble free......but now I have a problem. Boat cranks right up, but I have a significant grinding noise on the front side of the engine and it’s accompanied by vibration. Noise and vibration increase with RPM (I know, big surprise). Does this sound like a known problem?

Howdy,

Welcome aboard!

Instead of tagging on to someone else's thread, it's MUCH better to just start a new thread about your problem. You'll get far more people viewing it and will possibly get someone who has the same problem.

Regards,

Rick
 
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