'88 Johnson 15hp link 'n sync after cam throttle and carb top replacement

[KillerKilgore]

J15ECCS w/ remote controls.

Long story, short version.

Need steps and advise after replacing the broken throttle cam, cam follower (w/roller), and top carburetor cover. The old carburetor top #331735. I'm replacing with #337833 because I already have it. But using the original slow speed needle.

Long story.
Was on lake and engine acted like it lost a cylinder. WOT wouldn't do much but when throttled back was moving better. Thought I lost a cylinder (due to a bad coil) and the extra fuel going into the cylinder was causing all the trouble. And the it ran better at half throttle was not as much fuel causing more compression. Thought it was a bad coil. Tested coil back home and both fired but engine was cool. Figured one was getting hot and cutting out. So I put new power pack, 2 coils, plugs, plug wires on. Started and idles but no WOT.

Searched internet and seen it could be a drug stuck in carb somewhere. Took off breather and seen the crack had opened back up along the top of carb had opened back up.

Years ago when rebuilding carb seen it was cracked and I tried sealing it with clear nail polish. Worked for about 4 years. Now nail polish cracked and peeling off.

After taking the old plastic top off and putting the new plastic top on. (Brother bought it 4 years ago after finding out the other was cracked. But after i painted with nail polish.) I started engine again. Still no WOT.

Left idling and worked the throttle butterfly by hand and it reved up. That is when I noticed the throttle cam was broken. The cam follower roller was also missing the clear "cover" that is around the roller.

So now I have parts ordered, (throttle cam, cam follower w/roller, carb gaskets) but won't arrive until Monday the 22nd. And won't be able to work on it until the following Friday.

Can the old low speed needle be used with the new 337833 carb top. I hope so cause the new carb top with needle is $150.

 

[KillerKilgore]

First, I want to say thanks for the support.

To repair the above issue. After ordering and receiving parts, do a search for the "wayback machine" and go to that website. From here, in the top left go to "internet archive", then, "books", then "book to borrow". In the search box, enter what you're looking for. In my case it was "Johnson outboard". Then look thru the list to see if something relevant shows up. In my case a shop manual published by Clymer for Evinrude/Johnson outboard shop manual, 2 -40 HP 1973-1990. Just login and digitally "borrow the book".

A lot of shop manuals and other information can be searched and borrowed on many many subjects. When you have time, search your other interests.

Now go to Chapter 5, go to a 15hp for 1988 and follow the steps listed.

I had to install
1. The throttle cam with the screw lightly seated.
2. The cam follower with the screw lightly seated.
3. The carb top with the gasket that best matched the passages on the carb top and main carb body mating surfaces.
4. The low speed idle needle lightly seated with O-ring. Then back out 7/8 of a turn. I was able to use my original low speed needle.
5. Attached the throttle shaft amplifier to the throttle shaft butterfly. It's just an alligator clip with a piece of wire to see when the shaft 1st starts to move.
6. Advance the throttle until the timing mark on the throttle cam is aligned and very very lightly touching the cam follower roller. Use the screw on the cam follower to adjust as needed.
7. Start engine in test tank/barrel. Muffs won't work cause it will not give back pressure on the exhaust that is needed to set low idle in gear. Let engine warm up.
8. Drop RMP to 700-800 and adjust low idle needle to smoothest engine operation in forward gear.
9. For wide open throttle, engine doesn't have to be running. And I would not advise it. Since water will slosh out of test tank/barrel. And you may run engine without cooling water and ruin the engine. Have a runaway engine and it is just not needed. It is just a visual inspection. Look at the roll pin on the throttle shaft. The roll pin should to 100% vertical or straight up and down at WOT. It is 90° off set of the butterfly. So if the roll pin is straight up and down, the butterfly is perfectly horizontal and wide open. Not restricting air flow. If the roll pin isn't vertical adjust the screw on the throttle cam as needed.

10. Follow my directions and the directions in the above mentioned manual at your own risk. Remember the carb top, throttle cam, and throttle follower are made of plastic. Plastic gets old and can become brittle and break.

Also as long as I'm on the subject of the wayback machine. On that 1st page on the wayback machine website you can search pages that the internet web crawler has view over the years. If the website has been viewed/saved. There is a timeline at the top of the page showing years the site was visited. The main page shows months and date visited circled in blue. Once a date is selected, the time of capture is shown. Click on the time to see what the page looks like on that date and time. Once the historical page loads, there is a timeline at the top of the main page. In the timeline there are blue arrows. Use those blue arrows to go to the next capture date.

I know there is a ton. I mean a ton of information that could have been lost due to one reason or another. One such case is the, dare I say famous www.leeroysramblings.com site. Well that information, or most of it, can be accessed through this process.

Simply enter the url in the search box. In this case www.leeroysramblings.com . Then the most recent page with usable information is Jan 11 2024 at 11:45 am. Click on that time and see the page we all love. The links on pages also work. Some of the pictures or graphs may not be visible on the date selected. If that is the case, it may be possible to view the picture or graph on a different date using the timeline at the top of the page.

For example, I looked up the page containing exploded firearms drawings for a Winchester model 67. The page that came up was supposed to have 2 pictures but one didn't show. I used the blue arrows by the timeline at the top of the page to back in time and finally found a capture date that showed both pictures.

Best of luck with all information.

Killer Kilgore