How hard is it to switch to a dual prop? ('89 King Cobra))

[BigBabyLou]

I have a '89 King Cobra setup and was wondering if it would be too hard to switch to a dual prop lower unit.<br />1) Would this swap require any other change than the lower unit itself?<br />2) Can I do it myself?<br />3) How much would the parts cost me?<br />4) Is it even possible?<br />5) How much would this affect (positively) top speed, plane time etc?<br /><br />Thanks for any answers!<br />Lou<br /><br />P.S.: I have a 4-ton money pit and just a single engine (460) with lots of power and a dual prop setup would definitely be able to transfer this power to the water much better.

 

[dick]

Re: How hard is it to switch to a dual prop? ('89 King Cobra))

Only way to do it is to repower.There is no convervion avalible for that drive.

 

[Boatin Bob]

Re: How hard is it to switch to a dual prop? ('89 King Cobra))

There is a guy from Vancouver named Mike but his user name is Stratocaster who has done it but I think with a 5.7 engine. He went from a King Cobra to a Volvo duo-prop. I read his story on the BOC (Bayliner Owners Club) forum at http://pub12.ezboard.com/bbocweb, I'm sure if you post a question for him he should be able to help you out. BOC web page

 

[BigBabyLou]

Re: How hard is it to switch to a dual prop? ('89 King Cobra))

Thanks for the replies, I'll try to contact Mike and see what he had to deal with.<br /><br />Lou

 

[dick]

Re: How hard is it to switch to a dual prop? ('89 King Cobra))

BigBabyLou <br />If you find the post let me know this I got to see , Thanks

 

[Boatin Bob]

Re: How hard is it to switch to a dual prop? ('89 King Cobra))

Sorry guys, I saw Stratocasters answer, didn't realize he replaced the engine as well however I asked George on BoaterEd and here is his answer below, basically Volvo has a kit to do it and George has posted the phone number below<br />Author<br /> Topic <br /> <br /> TC340 <br /> RO # 1947 <br /> Orillia, Ontario, Canada <br /><br /> B.G.'s 3 <br /> Posted - 09/18/2002 : 11:59:21 <br /><br /> George....someone on another board asked a question about converting an OMC 460 King Cobra (drive only)to a Volvo duoprop, they were told it<br /> can't be done but I seem to remember a similar question here but can't find it, can you do it?<br /><br /> Boatin Bob<br /> George Van Parys <br /> RO # 6 <br /> Fortescue, NJ <br /><br /> DOLPHIN II <br /> Posted - 09/18/2002 : 12:43:08 <br /><br /> Not true, they even have a kit for it.<br /> Call Volvo tech service at <br /> 1 757 436-2800<br /> They can tell you all about it.<br /><br /> George Van Parys, http://www.boatfix.com

 

[P.V.]

Re: How hard is it to switch to a dual prop? ('89 King Cobra))

Sorry guys, it can't be done as simple as some may think. Here's why. If you have a Cobra/King Cobra with the shifting in the geasrcase(versus shifting in the upper housing as Volvo does)as OMC went with, there's no way to retro-fit the shift cable and housings to the later "Volvo way" of a single shift cable and cone-clutch shift mechanism in the upper. A '89 460 King Cobra has it the "old" OMC way. It's actually a V-8 outboard gearcase. Later, OMC did make a version of cone shifting but it's still not the Volvo "way". If you have a "VOLVO", you can retro-fit the lower to a duo-prop for something like $1500. or so.

 

[Boatin Bob]

Re: How hard is it to switch to a dual prop? ('89 King Cobra))

Well....we seem to have 2 schools of thought here. I guess the only way to know for sure would be for BigBabyLou to call Volvo tech Service at the number George gave above and ask them himself. Kind of curious to know myself since I have a couple of 89 460 Cobra's.

 

[dick]

Re: How hard is it to switch to a dual prop? ('89 King Cobra))

I think I know whats going on here,people might be get the OMC drives mixed up. Back in the mid 80's omc came out with Cobra drive, ( basicly same as a merc drive with sliding clutch dog shifting done in the lower )Then they came out with the King Cobra(early style) with a regular cobra upper and a bigger bottom case and gears( but still sliding clutch dog shifting )Then they came out with the new King Cobra(new upper and lower)with cone shifting done in the upper .Then OMC and Volvo went into a joint venture in 94 with both companys building identical drives( with the exception of the name and prop shaft spline count)These drivers came in both a single prop(SP) and dual prop (DP)and changing from a sp to a dp was done by dropping the lower case and installing the dp case.Now I think you got a early style king with sliding clutch dog shifting in a Bayliner? and there is no conversion for that.

 

[BigBabyLou]

Re: How hard is it to switch to a dual prop? ('89 King Cobra))

Thanks for all the replies, guys. I talked to Mike, he pointed me to some posts and articles and it turns out that the mod would cost me half the value of the boat anyway (if it's doable at all). <br /><br />So I dropped the whole idea. I guess I won't be calling Volvo tech service then. Sorry.<br /><br />Thanks for all the input, it helped me a lot.<br />Lou