4 stroke carbs: 9.9 vs 15hp

Tearing into a 9.9 and 15hp Yamaha carb and noting the differences

[@erichildreth7562]

I heard that's the only difference is the bore size and some jetting. I would keep the 9.9 carb and bore it out and jet it accordingly as to what the spark plugs show. Great video.

[@captain_315]

Thanks!!!

[@trommatizer69]

Nice video. Very simple and informative. Nice job I learned a lot.

[@creepycrawler43]

Great vid! Love learning more about carburetors!

[@jacobpetersen9430]

I looked at the engines and the f15 seens to have larger cylinders or cc if i understand right, there is also quite bit of weight difrence. But from a cc to horse power calculator we should be able to get more out of the 9.9 :)

[@captain_315]

I'm not really experienced with outboards, just a lifelong engine guy. It appears the early 9.9s were 323cc, the later ones were 212 and the 15s were bigger. I have the earlier 323cc version, which was the same as the 15s. Hell, whatever it is, the little bugger woke up big time! lol

[@captain_315]

UPDATE: carb swap- 22mph. 5mph gain with no other changes!

[@wouter12goNorth]

I did the same , but the engine no longer runs evenly from quarter throttle . Did you do any other modifications

[@captain_315]

@@wouter12goNorth not a bit, just bolted it on and went.

[@randallaycock2890]

With right prop and (On The Fly) jackplate you could get another 5 to 10 mph

[@captain_315]

@@randallaycock2890 I picked up 3mph with a 10P prop and a little cupping, and raising the engine up 2.5". Jack plate will pick up more?

[@joshmcdonald9508]

That made a lot of sense now that you explained it. I have a Mercury 9.9 and I imagine it's roughly the same idea. Is there a reason for adjusting the float height? Isn't there just one good setting?

[@captain_315]

Im not very experienced with outboards at all, but yes it appears the Mercs are pretty much the same thing. Shouldnt be any reason to change float height unless the tab on the float got bent or banged around. Im sure theres a spec and wouldnt hurt to check it.

[@gordonlechner4474]

What is the diameter of the hole on the intake manifold? Does it match the 9.9 or 15hp throat size? If it is smaller to match the 9.9 carb will there be any conflict with the butterfly flap on the 15 hp carb and if it is smaller than the 15 hp will that impact any gain in hp? I'm looking to do something similar on a mercury. Thanks!

[@captain_315]

The carb outlets and butterflies are the same size so no issues with the intake, bolt it on and go. Please update the results, you wont believe it!

[@gordonlechner4474]

@@captain_315 I had bought a 15hp carb, but the outlet on the intake manifold was substantially larger. This was for a Mercury so maybe different on Yamaha. I think I read something about the mercury 9.9 changing the size of the engine block at some point. Hard to find specific info and very confusing.

[@captain_315]

@@gordonlechner4474 it is super confusing! What year is your merc? Yamaha did change from 323cc to 212cc but not sure when, mine was the 'bigger' 323cc (2007), those carbs were interchangeable between merc and yamaha.

[@gordonlechner4474]

@@captain_315 It's a 2011 8 hp, which is supposed to be the same as the 9.9. supposedly the 8 hp is a detuned (carburetor) 9.9. But again, that is confusing because the part numbers for the available carbs are the same..

[@stevethompson8799]

Have a 2014 yahmaha. Could you please tell me were you bought the 15 carburetor from? Thanks can't find one that will fit.

[@captain_315]

Im not familiar with what the 2014 has on it, but you SHOULD be able to go on A**zon and find one. Sorry Im not much help there.

[@henrikfridmann3194]

Hi, I have a 9.9 hp I 2004 I want to upgrade to 15 hp, do you have a link to a Chinese page where they sell this carb ?

[@captain_315]

This is the same style I bought but not the same vendor, so check your measurements. Let me know the results! www.amazon.com/VIPIH-Carburetor-Replacement-Outboard-66M-14301-12-00/dp/B0CRQT858W/ref=sr_1_7?crid=1RHKW1VZC4ZG4&dib=eyJ2IjoiMSJ9.R7JcLnJsUlo_Wm6L_I4Blm0hwqS6yAax_po7v4NhqssGmCHulCe7do0w6AN3-J2R73jdIRpf30dodsruExXJ6kPRx-18HZVo6bA2_wHQ2CZAIOFBYiwoF9tIaCmVdV7Ey5nF7zqyWVQ8pnufK5brYjOlzwbfeg1yaf3KKvL8p0YOHcNNHzzxUhifbyjq1mHK1XW2vVZGHrYszWS_xy3uxsoVgNcNu3_hWIEnqJwO12WvfDGR0EhIq-e-pW7zS6nIU44iI6zknPUMylghaghNdh09SLc66PyRc3ken-RLRSc.jpGXi9RHYplu9fFME5MaVeby27vpaxL0YXYz4ZOiUyY&dib_tag=se&keywords=yamaha+f15+carb&qid=1716911166&sprefix=yamaha+f15+carb%2Caps%2C122&sr=8-7

[@rexxx927]

So I have a F9.9MSHC 4 stroke high thrust 6G9 group from 2004 and has the warm up solenoid on the top wax operation I believe OEM is discontinued and would wonder if I can use this one and if the solenoid simply mounts to the top of the ones you have on the table via the two screws on top? any direction is appreciated in advance. Cheers crowley and CPN also iboats are conflicting it is possible is carb would be different but work?

[@captain_315]

Wow I honestly have no idea, never messed with any with the solenoid. Sorry.

[@rexxx927]

@@captain_315 No worries is not really a solenoid but a wax element when heated the pin closes of the choke circuit and its not failing but need a carb for it with one Thanks anyhow keep up the good videos

[@captain_315]

@@rexxx927 That is so cool, never heard of such a thing! We're never too old to learn. Thanks!

[@pauliuskareckas6406]

Hello I have 2014 yamaha 9.9, guy i bought it from said that i can't upgrade it, couse it's not sport. Just want to find out it's true or not. He said if that gonna be sport you could upgrade to 20hp. But it's not sport so you can't upgrade at all...

[@captain_315]

Never heard of such a thing, but im not an expert on outboards either haha.

[@josephauld6565]

I have a 98' suzuki 15hp 4 stroke on running 2800 rpm wide open.. need new jets? It wont idle unless raise the throttle. Need new carb?

[@larryalexander4833]

I suggest a thorough carb cleaning first. Idle circuit is clogged more than likely if it is stock carb.

[@cobramarine912]

Hello. Can i modified my tohatsu everrun 18 and make it faster by changing main jet

[@captain_315]

I am not sure. If the engine isnt modified there should be no need to change the main jet.

[@gordonlechner4474]

Did you ever do the video with the F15 carb on your jon boat?

[@captain_315]

I did not. Unfortunately I lost the 'before' vid, so not much to compare.

[@mchristofas]

Captain, I'm looking for a top engine cowl for a yamaha 15hp 4stroke 2005 if you or know someone message me please!

[@captain_315]

Will keep my eyes open for ya.

[@kostaswolf1978]

Same thing on Mercury 9.9 to 15hp??? Thanks

[@captain_315]

I believe so.

[@kostaswolf1978]

Has only 209 cc...do you think can do 15hp?

[@captain_315]

@@kostaswolf1978 I think its worth a try!

[@crainoxlong2338]

Can you do that to a 6hp yamaha to 9.9hp

[@captain_315]

Really not sure. I am an engine guy but this is the only outboard ive ever owned haha, im far from an expert.

[@crainoxlong2338]

@@captain_315 your probly right

[@garycotz563]

Do you have a link to that chinese carb?

[@captain_315]

I dont know how to copy a link to put here haha sorry. Just search the big sites and make sure it has the accelerator pump as shown in the vids.

[@HAcera-hs3hw]

@@captain_315 would be really helpful if you had more info on the carb. Hoping you’ve tried again to highlight and right mouse ‘copy and paste’ (computer) or long touch the link and ‘copy and paste’ (mobile). Thanks

[@captain_315]

@@HAcera-hs3hw www.amazon.com/Carburetor-66M-14301-11-66M-14301-00-4-stroke-outboard/dp/B01F0YGWJI/ref=sr_1_2?crid=JALC0DDHXG99&keywords=yamaha+F15+outboard+carb&qid=1663085069&sprefix=yamaha+f15+outboard+carb%2Caps%2C106&sr=8-2&ufe=app_do%3Aamzn1.fos.006c50ae-5d4c-4777-9bc0-4513d670b6bc

[@MrTk6969]

My 9.9 has an accelerator pump

[@captain_315]

Interesting! Never heard of that.