Motor Identification Help

Oathkeeper

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Hello, I am trying to find parts/information for a motor in a boat I just got. From what I can find the Model Number is 983842 - Serial number T0439537 or TO439537. The remaining details on the motor say OMC - Cobra Outdrive Systems, on the engine itself the word Osco is written in cursive and three letters GLM can be seen. The only history I have is from a conversation stating the motor was from another boat and that it was a 94 - Mercruiser may or may not of been mentioned.
 

Scott Danforth

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Got any pics?
Osco and GLM are aftermarket parts companies, so sssume the exhaust has been changed

The drive model 983842 is a 1986 drive.

Motor serial number tag sgould be on block, just above starter
 

Oathkeeper

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The boat I got is a 1987 SSB VS 23 foot boat, i'm also having trouble finding information about the boat name/type. Im new to boating, like day number 3 new but this is already a fun and challenging project.
 

Scott Danforth

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most of your pics of of generic stuff such as the firing order (standard small block chev stuff there). was hoping for a clearer/brighter pic of the motor from an iso shot to see the side of the manifolds as well as the thermostat housing.

my guess is the motor was replaced at some point since the motor has a remote oil filter. do you have 8 intake bolts or 12?
 

Lou C

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Looks like someone swapped a Mercruiser motor onto an OMC Cobra system; you can see the Merc flame arrestor and thermostat housing. It can work as long as the exhaust matches up to the OMC Y pipe and the OMC shift assist module/switches are in place and working.
 

Oathkeeper

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@Scott Danforth, sorry I don't have much experience with motors, (I have no clue what im looking for) so I'm trying to find what you need me to get for you. I took a few more pictures, maybe some of these newer ones might help.






 

Oathkeeper

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Lou C {It can work as long as the exhaust matches up to the OMC Y pipe and the OMC shift assist module/switches are in place and working.} How do I accomplish this task? I was told I had to find a way to get the throttle cable attached.







It should be noted when the motor was started it ran without issue, the propeller spun, the throttle when pushed fired with no identifiable issue, the motor was lowered and raised without issue, though again there was a hose/tube that was leaking.

The bottom hose/tube in this picture. I cant remember what the guy I got it from called it.
 

Lou C

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You've got a bit of a mess there.
First you need someone who can figure out how to hook up the OMC throttle cable to the Merc/Weber carb. There are adaptors that can make this work; take a look over at Michigan Motorz. The leak is a trim line for the tilt and trim system. You might need a marine mechanic to straighten this out before you can use the boat..
When they pulled this Merc dressed engine out, they should have switched over all the OMC stuff like the Rochester QJet carb and the OMC throttle bracket.
 
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Oathkeeper

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Yeah his main issue was funds/time to continue this project the storm set him back too far to continue working on it. I figure If I can resolve the lingering conversions/updates and modifications needed on my end I can take it to a shop to get a tune up and be water ready. Although there are other much needed updates that I need to do to the boat console before I feel confident enough for the water.
 

Lou C

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You also have to make sure that the shifter bell crank for the lower unit on the starboard side of the engine does not hit that breather hose on from the carb to the valve cover. That will keep the drive from going all the way into gear and will cause jumping out of gear. This is why Edelbrock/Weber carbs do not work well on an OMC Cobra application, the carb is too wide on the side this next to the shifter linkage. OMC engines came with the Quadrajet 4bbl until about '90 or so and then they switched to a Holley 4160 4bbl I believe. Ether one of these carbs fits the engine set up better than the Edelbrock/Merc/Weber carb.
​I noticed a hold down screw for the distributor cap missing. I strongly recommend that you get this boat to a real marine mechanic to sort out these problems, to make it safe to operate. The engine itself will work fine, its the carb/linkages that need attention. Make sure the mechanic has OMC Cobra experience and will know how to make sure the shift linkage is set up right and the ESA system works. Otherwise this boat will either not shift right, & not come out of gear.
 
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