olhippie1: Once and for all...It is absolutely true that the carb is the only
difference between the 9.9 and 15 h.p. '76 model Johnson outboard!
MetalTeamster: exhaust was diff on 15s....
chargerkid2011: Is this motor pretty reliable? Im getting ready to purchase the same motor
troyusaguy: I have the exact same motor. I was inspired by this video and bought the
15hp carb. I cant wait to try it, hopefully my buddy can come over and swap
the carb. Ill keep you posted. How do you like these older motors? Ive
thought about buying a newer one, 4 stroke, but this way seemed to fit my
Tater79bj: Nice vid, but your only half right with the carb change. Hp gains are built
into the block itself via porting. The 9.9 and 15 blocks may be indentical,
but I bet money the exhaust ports on the 15 are bigger. You may gain a
little with the swap, but not the full 15. Its like 2 to 4 barrel swap on a
bsrktm1: In 1976, the ONLY difference between a 9.9 and 15 was the carb. It has a
larger venturi and bigger jets than the 9.9. The 9.9 is a restricted 15.
Later models added the tuned exhaust to get a full 15 prop rated Hp. Early
(before about 1980) models were flywheel rated.
aussiepaul49: The 9.9 uses the same power head, exhaust housing and reed plate. All those
items use the same OMC part numbers. There is no difference. I've just
replaced a broken reed on a 1982 15 hp using the reed out of a 1979 9.9 and
I can tell you they are exactly the same.
BOATSandAIRSOFT: Well I found my carb on eBay so I suggest looking around on eBay for one
and I went to my local dealer and asked if he had any 15hp Johnson carbs
and he said that they have not sold a carb brand new since 1976 when the
motor was changed so I suggest to look around on eBay
bob o: is this a 2 stroke
mjtj456: This kid is an idiot....Changing the jets or the carburetor on a 9.9 hp
Johnson won't turn it into a 15hp engine...The engine will run slightly
faster, but the exhaust ports are larger on a 15hp engine and you
definitely will not be achieving a 15hp rating or anything even close....
BOATSandAIRSOFT: @1MACVSOG1 you should take of you lower unit and make sure that the shifit
rod and linkage are in proparly anf if not lossen one of the screws on the
linkage and slide the shift rod down untill it is fully in place
Ferdinand den Bleker: awsome! Do you think I can do the same with my 9,9 hp from 1975, and my 15
hp from 1976? Someone gave me the 15 hp but I'm not sure if I can get it
fixed so I was thinking about switching the carb. Is there really nothing
else you have to change? Not even the exhaust or the ignition? greatings
from Ferdinand (from the Netherlands)
iCloud: changing your carb wont make it 15 hp it will give you more torque and
maybe 1 hp extra but over time it will wear and just act like the stock
carb if you want to add more power just go buy some freaking nos or a bigger
craig irvin: Hi there, that vid was pretty helpful! i have the same model as that and
i'm haven a nightmare of a time tryin to find a 15hp carb, any
96Duelfuel: In another video, the fellow changing the carb took off the starter, and
cautioned everyone, that when unscrewing the starter bolt and wrapping tape
around it, to use extreme caution, as the spring is under quite heavy load
and fly out and hit you (i.e. your eye). This is a very important piece of
MrPequod1: Be aware that this is not the only difference in the 9.9 and 15. I did the
swap on the same engine. I didn't gain much. The exhaust housing is bigger
on the 15 and the leaf valves also need a shim to open them up. In order to
do that ,you need to take the block out. I have done that, and It is not
advised unless you have some prior outboard motor experience.
BOATSandAIRSOFT: @SouthernCross33 you should look on the side of your motor there should be
alittle plate that has numbers on it the one that says serial number look
at the last two numbers and that should show you how old your motor is so
for example ********88 means that the motor is an 1988 or what you can do
is be more specific instead of looking at the last two numbers type in the
whole serial number in the internat and type in behind it johnson serial
orignalbuckaroo: I think you're right, beside, the 76 still had points and condenser!!
Electronic started in 77, then we started to have real prop horse power
which made a huge difference in the speed !! TNX for the comment!! :)
dana woolaver: i just got one of these... here is a stupid question is this motor a 2 or 4
ArnzT100: Any young person who can change out a carb on an old 'Rude has a lot on the
ball. Let's be more encouraging toward a kid who knows more about 2-cycle
carburetors than your average adult. He's going to be an awsome mechanic.
1kruzer1: mjtj456, I suggest you check your facts before you stoop to name calling.
In 1976 the ONLY difference between the 9.9 and 15 is the carb. No
difference in ports, no difference in exhaust tube (tube change came later
when they switched to prop shaft rating), and no difference in reed
assembly. Change the carb and, if it doesn't quite rev to the 15HP factory
RPM spec, change the prop so it revs between 5500 and 6000, and PRESTO you
have the identical engine as the factory 15.
iCloud: @BOATSandAIRSOFT erm let me see you goto you local car tuning shop you buy
a nos kit and you get a marine adaptor for the engine and the solenoid
power for everything etc hook it all up start engine open the tank of nos
to let the gas flow hit the button and away you go ?
jaden crochet: Great video and where did you get the 15hp carb?
bsrktm1: I'll take the bet and your money. A 9.9 is a restricted 15. Same block,
crank, rods, porting, compression, reed block- Does it make sense from a
manufacturing standpoint to change all that? Carb IS THE ONLY difference in
1976. Reed shims (they add VIRTUALLY no Hp), and tuned exhaust were added
to later 15s to get a full 15 PROP horsepower. 15s also were rated at 1000
1MACVSOG1: hey buddy I was wandering you could help me I just pick up the same motor
for 50 $ it runs great all for 1 thing when you get going full throttle
under about 600lbs load "boat and me in it" it wants to jump out of forward
?? Back into neutral I can hold in in forward and it will run fine was
wondering if ya knew? What the problem was
Fauerbachbrewery: good work and good camera work. Helpful information!
neo71665: Difference in the exhaust also. The carb swap is a big part of the
difference but its not the only one. You might have made it a 11 or 12
orignalbuckaroo: Nope, not only the carb !! To do this job correctly, he needs to change the
exaust tube as well, if not, the engines wont have full performance and it
will be darn hard on gas !!!
wiliam sullivan: Great job. Laugh at the negative comments. Talkers are always talking about
putsstuff: He is not an idiot he is right the 2 blocks are identical only the carb was
Jelmer Gunnink: Is it the same thing if you have a electric start?
BOATSandAIRSOFT: @Troyusaguyi love these type of motors the are very reliable and are great
runners I have recent lye sold this mototr and upgraded to a little bit
newer one a 1988 9.9 Johnson and I lone it now I would love to keep on
hereing about you boat motor
bsrktm1: @daervs100 15hp OMC carbs from 1974 to 1992 are interchangeable. Newer (mid
80's) are plastic on top and bowl. Keep in mind that many people don't know
the differences between the 9.9/15 carb since they look externally the
same- it's the venturi area that is the difference. Check Craigslist in
your area. I've bought several complete non-running 15hp motors for
100-150$. 15hp carbs on Ebay can be that much alone. You'll have lots of
spare parts- BTW- I've bought 9.9's that had a15hp carb already.
leon karras: exw mia johnson 9-9hp toy 1984 mporw na th kanw 15 mono me ydatanthrakes h
tha xreiastw k exatmish??????
BOATSandAIRSOFT: Yes the gear ratios are different in the lower unit back in 1976 the
measured the horse power by the power head now after they 1976 they started
measuring the lower unit horse power at the bottom end
christoph1039: Good job man. Say thanks to your crony there too for the good recording.
Thanks for the clear steps. Used this video to clean the carb on my 1981 15
SouthernCross33: Hello, can you tell me how to find the date of my 15 hp johno. I bought a
25 hp suzuki motor to push my old glass boat along quicker but have found i
can't tell which is quicker. I prefer the johno though
How to turn a 1976 9.9hp Johnson to a 15hp(Carb Exchange)4.3
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