TinBoats.net
The original aluminum boat site!
Forums
New posts
Search forums
Blog
What's new
New posts
New media
New media comments
Latest activity
Media
New media
New comments
Search media
Members
Current visitors
Log in
Register
What's new
Search
Search
Search titles only
By:
New posts
Search forums
Menu
Log in
Register
Install the app
Install
Forums
Boats
Motors
'93 Johnson 25HP, Can't get it to idle right...VIDEO!!
JavaScript is disabled. For a better experience, please enable JavaScript in your browser before proceeding.
You are using an out of date browser. It may not display this or other websites correctly.
You should upgrade or use an
alternative browser
.
Reply to thread
Help Support TinBoats.net:
This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.
Message
<blockquote data-quote="maintenanceguy" data-source="post: 474231" data-attributes="member: 24227"><p>Random thoughts:</p><p></p><p>Seems to be hunting when at idle. rpm up, down, up , down. Often indicates a fuel delivery issue. Check tank, fuel lines, pump, vacuum that drives pump, filter, water separator, and fuel quality. If this stuff is original or older, I would replace everything from the tank to the carb.</p><p></p><p>Assuming the carbs are now good, it still could be the idle air adjustment on the carb - if that hasn't already been adjusted correctly. You'll need the factory manual to get the procedure to set that correctly.</p><p></p><p>Finally, the least favorite. How is the compression? a bad head gasket, scored cylinders, bad compression rings, etc will let the expanding gasses from combustion escape from the cylinder. At high RPM you are making a lot of expanding gasses so it doesn't effect performance a lot. At idle, when you're barely making enough to keep the motor running, these problems will make a big difference.</p></blockquote><p></p>
[QUOTE="maintenanceguy, post: 474231, member: 24227"] Random thoughts: Seems to be hunting when at idle. rpm up, down, up , down. Often indicates a fuel delivery issue. Check tank, fuel lines, pump, vacuum that drives pump, filter, water separator, and fuel quality. If this stuff is original or older, I would replace everything from the tank to the carb. Assuming the carbs are now good, it still could be the idle air adjustment on the carb - if that hasn't already been adjusted correctly. You'll need the factory manual to get the procedure to set that correctly. Finally, the least favorite. How is the compression? a bad head gasket, scored cylinders, bad compression rings, etc will let the expanding gasses from combustion escape from the cylinder. At high RPM you are making a lot of expanding gasses so it doesn't effect performance a lot. At idle, when you're barely making enough to keep the motor running, these problems will make a big difference. [/QUOTE]
Verification
Post reply
Forums
Boats
Motors
'93 Johnson 25HP, Can't get it to idle right...VIDEO!!
Top