I've wondered about this because the motors are the same size and look identical. I thought it had to do with cylinder volume.

It is important to note that there are more differences besides just the carburetor on many of these engines. On the engine pictured: The 8hp actually has a larger intake manifold and exhaust ports when compared to this 6hp, so changing just the carburetor isn't going to do much. In this case, you have installed a 9.9-15hp carburetor on this 6hp engine.

@donk499

Жыл бұрын

There is no guarantee that this 9.9-15hp style carb will actually improve performance, it may actually decrease performance. Just because the engine seems to be "screaming" in that bucket doesn't mean it will perform well on a boat. This is an "experiment", buying those used carburetors is very expensive these days. While I agree that those older carbs are much more simple/reliable and easy to repair than those horrible new style carbs, doing this is a very expensive "experiment". The RPM limiters are not on all of these power packs, the limiting RPM will be written on the pack if equipped. Keep in mind that the older 6-8hp engines have aluminum connecting rods, over revving them will stretch the rods, allow the needles to escape and end up in catastrophic failure.

@BoatMotors

Жыл бұрын

Please show me the difference: 1 www.marineengine.com/parts/johnson-evinrude-parts.php?year=1987&hp=6&model=J6RCUD 2. www.marineengine.com/parts/johnson-evinrude-parts.php?year=1987&hp=8&model=E8RCUD

@ct1762

6 ай бұрын

@@BoatMotors note the block #'s are different. as i said above, its cylinder head, exhaust, porting, carb and reeds. good luck with your motor.

Yeah, a carburetor filled with gunk and debris will never work properly. At least it will fail when you're out on the water and far from land (Murphy's law). We have a 7,5 HP and we'd like just a tad more power. This video was very helpful. Also, we have a 6 HP air-cooled secondary engine which we'll have a look at too. :)

@BoatMotors

2 ай бұрын

Thanks!

I will be doing this thankyou I have a 1977 6hp evinrude,

@ct1762

6 ай бұрын

no lol. completely different motor!

Have you done a speed comparison using the same boat to see if it did in fact increase the power?

@BoatMotors

11 күн бұрын

No

there is a difference in the porting (2 giant intake and exhaust ports vs. three little ones), the exhaust plate of course, the cylinder head, and the reeds. adding an 15hp carb will not do a thing. just make it idle a lot worse. i recommend studying how a 2 stroke works. the 8hp was much more powerful than the 6hp versions, especially the small rod 1987-up motors.

Awesome video!!! Just found your channel and i am really looking forward to view your back catalog of film. I was messing around wiith V4 omc but now want to see what can be done with the smaller 2cyclinders

@BoatMotors

2 ай бұрын

Thanks!

❤

Thank you. I have this motor for my Catalina 22 Sailboat: "1966 Evinrude Outboard 5 HP angler 5603". I think it is a long shaft. I am going to rebuild the carb, plugs, replace points and gap/set dwell, and then once it is running good (stock) I am going to cut the snorkels to get more are and adjust with stock CDI. Maybe I will get 6 HP??

@BoatMotors

Жыл бұрын

If I understand correctly you have 1966 Evinrude 5HP long shaft. This motor is very strange combination from 4HP and 6HP parts. I'm attaching 2 different videos, first is how to service 4 HP which is pretty close to your motor and the second video shows how to modify the engine hood to get more HP. kzread.info/dash/bejne/mqOblrOyoNK0aKg.html and kzread.info/dash/bejne/ipV629ipo7fVndI.html

@benkanobe7500

Жыл бұрын

@@BoatMotors Thank you for your responses and especially the links!

Wow !😊

@BoatMotors

9 ай бұрын

Thanks!

Evening. Your Videos are very very good and informative. A question for you please. On my Johnson 8hp Two Stroke. The Manual states The Mixture Screw should be set at 2.1/2 Turns Out . I am finding it Runs and Idles About 4- 5 Turns Out. Can you help me please About The Correct Setting; As I do seem to find The So Called 'Lean Sneeze Postion' Also I am having Problems in Setting Up The REMOTE THROTTLE AND GEAR CABLES DUE TO 33C LENGTH OF CABLES!! YOUR HELP AND EXPLANTION TO HELP ME WILL BE VERY MUCH APPRECIATED AS I MENTAL HEALTH ISSUES. KIND REGARDS. ANDY.

@BoatMotors

10 ай бұрын

If the motor is working good on idle speed and high RPM don't worry for the idle needle. Some motors are ok like that. If you have carburetor problems you need to clean it and install new repair kit. Regarding the cables please follow the link to find your motor and the correct cables. www.marineengine.com/parts/johnson-evinrude-parts.php

Hi, did you finally try it out on the water? Was there a difference in the performance? Actually thanks for making this experiment. I did a carb swap with a 7.5carb, which definetely worked out. Ich still have some 9.9 carbs though. 👍

@BoatMotors

Жыл бұрын

I don't have available boat at this moment. The motor definitely is no 6HP with this carburetor

@aussenborderclassics

Жыл бұрын

@@BoatMotors you need to get one as soon as possible. 😉 One can hear the different sound and it seems to have more power. But i am really curious, If it works out on a boat or if for example the prop starts slipping.

@aussenborderclassics

10 ай бұрын

I just tried it and put a 9.9hp carb on an 1990 8hp. It works fine and i believe it definately has more Power: kzread.info/dash/bejne/qKiBm9ynnpDUkZs.html

@GOD-xe5gk

10 ай бұрын

O HOW I WILL LOVE TO GET ONE I HAVE A 1969 6 HP OUTBOARD I LOOKING ALL OVER FOR A 9.9 CARBURETOR FOR IT CAN'T FIND ONE I LIVE IN TRINIDAD.

Like it

@BoatMotors

4 ай бұрын

Thanks!

Afternoon Sir. What Size Main Jet is in The 15hp Carb You Fitted To Your Johnson 6hp . I am going to do the same. Is The Main Jet A Number 48??

@BoatMotors

Жыл бұрын

Number 54

@andygelston9182

11 ай бұрын

@@BoatMotors .Thankyou Sir For The Information. Be Very Blessed in Your Videos. Keep Them Rolling Please.

@BoatMotors

11 ай бұрын

@@andygelston9182 Thanks!

I don’t know much about this conversion but with the 9.9 to a 15hp you need a 15 carb AND a 15hp exhaust. I would think this conversion would require both a carb and a pipe. The 15 will rev 1000rpm higher than 9.9. Both the 9.9 and 15 are very good motors but the 15 is amazing for a 75# motor.

@BoatMotors

8 ай бұрын

Yes I'm agree 9.9HP and 15HP will require both a carb and a pipe. 6HP and 8HP have the same exhaust pipe. The only difference is the carburetor and the CDI.

This is very interesting. --- Is there some pieces in the 6hp that are not tuff enought for an upgrade to a 8 hp by a change of the carburator ?????

@BoatMotors

8 ай бұрын

No

@sergenaud731

8 ай бұрын

@@BoatMotors ---- That lead me to this question: Does ALL parts of a 6 hp (including in the foot, propeller, etc...) fit in the 8 hp ????? Because if yes, it's more (good) used parts to repair the 8 hp.... -- So, can we say that Johnson motor are really good motor to buy ????? = equal in quality as the Evinrude, or even better ???

@BoatMotors

8 ай бұрын

@@sergenaud731 Yes this brands are one of the best. The only difference is the carburetor and CDI unit in 6 and 8HP. Johnson and Evinrude are identical motors. Please watch the following videos to learn more for Johnson, Evinrude and OMC: 1 kzread.info/dash/bejne/mXZ3l8mJoKXdprA.html 2 kzread.info/dash/bejne/f4d3maWuic7JaZM.html 3 kzread.info/dash/bejne/eaag3LaDmtPKgqg.html 4 kzread.info/dash/bejne/n2mXpZmgcpXRY9o.html 5 kzread.info/dash/bejne/nqWNrNibnNqsfJs.html

@sergenaud731

8 ай бұрын

Do you mean that Johnson 6 is the same as the Evinrude 6 and 8.... ????? The only difference between those is only the carburator and the.... ---- If YES, the better thing to do is to buy the 6hp Johnson or Evinrude 6hp, who have the BEST compression and the lowest price, and convert this one in a 8 hp ?????

@BoatMotors

8 ай бұрын

@@sergenaud731 Yes the motors are identical. Don't forget the carburetor is expensive

Just go and find and 8 horse, its much easier.

@ct1762

6 ай бұрын

right. its cylinder head, block (porting is much better in the 8hp), exhaust plate, reeds and carb. the reeds are 6 petel vs 4 for the 6hp and old 7.5.

What part number carb you install?

@BoatMotors

Жыл бұрын

15HP Johnson Evinrude carburetor 1974- 1987