1999 90hp Johnson Outboard Carbs

[Sea Hunt Triton 172]

I am somewhat new to the outboard engine world and would like to rebuild the carburetors on my 1999 90hp outboard Johnson engine. I have worked with motorcycle engines in the past given both my son's raced motocross for several years, however they were only single carbs. Are there any specific items that would require someone with experience to perform this task such as synchronizing the four carburetors or special tools needed?

Any guidance to the difficulty of this task would be greatly appreciated.

 

[Chris1956]

Re: 1999 90hp Johnson Outboard Carbs

Go to the crowleymarine.com website and look up the carbs. You will see that it has four carbs without choke or throttle plates, and two throttle bodies, which house the throttle plates. A fuel primer provides the choking function.

A service manual will tell you the number of turns from light seating for the idle mixture. It is some obscure number not 1-1/2 like you are likely used to. Tuning four carbs is a bit tricky, luckily you only need to set idle mixture. there are some synching of the throttle plates that you may need.

 

[Sea Hunt Triton 172]

Re: 1999 90hp Johnson Outboard Carbs

Thanks Chris,

I do have a service manual and will be looking this over in more detail over the weekend.

I see you mentioned the fuel primer provides the choking function, could you elaborate a bit more on this item? I noticed that behind the air box there is a small red lever with a air nozzle stem and cap (looks like the stem on a bicycle tire that you could pump air into???) and was told this is a manual choke for cold starts. What is the air stem for?

 

[tashasdaddy]

Re: 1999 90hp Johnson Outboard Carbs

Primer Solenoid
the primer replaced the old choke butterflies in the carborators, pushing in the key activates it, like the old choke plates, but injects fuel directly into the intake.
The red handle is used when your battery is dead, and you have to rope start. You move the handle 180 degrees.
Normal operating position is with the handle back over the body of the solenoid, like in the picture below.

 

[Sea Hunt Triton 172]

Re: 1999 90hp Johnson Outboard Carbs

Chris,

I forgot to mention the service manual I have is the SELCO repair manual. Should this book be appropriate for what I am trying to do or is the official manufacturers book more descriptive?

 

[Chris1956]

Re: 1999 90hp Johnson Outboard Carbs

OEM book is better, but if you have experience, the seloc should suffice for the simple carb job you want to do. if you need detailed info on the warning systems, wiring or other stuff that changes a lot over the years, the OEM book is essential.

 

[Sea Hunt Triton 172]

Re: 1999 90hp Johnson Outboard Carbs

tashasdaddy,

Why is there an air stem with cap similar to a bicycle tube? Is there ever a need to inflate???

Thanks for th picture its worth a million words. This is the first time I have ever used a forum and the results have been extremely helpful. I commend all of you that provide this information for us lonely souls that are lost and confused...

Signed,
Feeling a little better in CT...