Parts Manual - 2003 Mercury 9.9/15 HP

MarvinGabriel

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Hello. I've been trying to find an online parts manual for the Mercury 9.9 4 stroke, and the 15HP 4 stroke. I'm trying to identify the parts differences between the two, for a conversion. I know that the carb is different, but suspect I need to change exhaust porting as well. They're both 323cc engines, so I'm sure the engine will work fine. Just need to open up the input and output of the airflow...
 

GA_Boater

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Thank you, but I still can't see anything that relates to the exhaust. I guess they just don't carry those parts.
Exactly what are you looking for in exhaust? A 4 stroke isn't like a 2 stroke with tuned ports in the cylinder wall.
 

MarvinGabriel

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Exactly what are you looking for in exhaust? A 4 stroke isn't like a 2 stroke with tuned ports in the cylinder wall.
I know that. However, any IC Engine is nothing more than an air pump. And the 323cc 4 stroke engine is sold as an 8, 9.9, and 15HP engine. It's just de-tuned for the lower horse powers. I know that the air throughput is the cheapest way to de-tune, and realize the carbs are different. I'd like to see the breakdown of the exhaust components, to see if they restricted output there, for the 9.9. All I can find is the Exhaust Cover (which is the same part # for all three outboards.)
 

MarvinGabriel

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I know that. However, any IC Engine is nothing more than an air pump. And the 323cc 4 stroke engine is sold as an 8, 9.9, and 15HP engine. It's just de-tuned for the lower horse powers. I know that the air throughput is the cheapest way to de-tune, and realize the carbs are different. I'd like to see the breakdown of the exhaust components, to see if they restricted output there, for the 9.9. All I can find is the Exhaust Cover (which is the same part # for all three outboards.)
Please keep in mind...I'm not being lazy, or purposely difficult. I don't mind doing research. The Factory Service Manual for this engine doesn't even mention exhaust components, and I can't find the proper parts manual, so it's tough to do this, in my current situation, out here in the sticks! :) I do appreciate the assistance.
 

Faztbullet

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Looking at part only thing found is carb difference.. Cam is same as is block.
 

Sea Rider

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The converted 4 stroke 15 HP carb motor probably runs with slight more timing advance than the standard 9.9 one, a matter to check the Merc's Service Manual timing specs if ever mentioned ? If those are exact same rebadged Tohatsu versions the Tohatsu's Service Manual will surely mention both specs...

Happy Boating
 

MarvinGabriel

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The converted 4 stroke 15 HP carb motor probably runs with slight more timing advance than the standard 9.9 one, a matter to check the Merc's Service Manual timing specs if ever mentioned ? If those are exact same rebadged Tohatsu versions the Tohatsu's Service Manual will surely mention both specs...

Happy Boating
Thank you, Sea Rider! I'll check the service manual, and make the proper adjustments. I'm assuming that the carburetor I just ordered from iboats.com is OEM, and that I'll be able to get rebuild kits when the time comes?
 

Sea Rider

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Thank you, Sea Rider! I'll check the service manual, and make the proper adjustments. I'm assuming that the carburetor I just ordered from iboats.com is OEM, and that I'll be able to get rebuild kits when the time comes?
You're welcome, those motors are currently being fabricated so long live the spare parts availability, a proper serviced and maintained motor will not requiere rebuild kits any time soon...

Happy Boating
 
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