johnson 18hp will not idle

Joined
Aug 9, 2004
Messages
24
i have an fd-15 that will not idle..it runs fine when you have the throttle up..but when you bring it to idle it dies...what do you think is wrong w/ it...thank you
 

Paul Moir

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Nov 5, 2002
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6,847
Re: johnson 18hp will not idle

Most likely the carb needs a good cleaning, particularly the idle circuit. Does the idle mixture control 'do anything'?<br />Get a rebuild kit from your local Johnny/Rude dealer. They're like $2 more than aftermarket, and they come with a new plastic float to replace the troublesome cork one.<br />Needless to say, a service manual is manditory.
 
Joined
Aug 9, 2004
Messages
24
Re: johnson 18hp will not idle

the idle mixture control does nothing w/ it....i have tried that...i thought that might be what it was..can you think of any thing else it might be?
 

Paul Moir

Admiral
Joined
Nov 5, 2002
Messages
6,847
Re: johnson 18hp will not idle

Not really - If the idle control does nothing, it's a good indication that the idle orifaces it regulates are clogged up. They're tiny and easily clogged. You can probably 'prove' it by choking the engine a bit at idle. If that seems to help, it's definitly running too lean.<br />If you can identify which end of a screwdriver is the handle, I suggest you get a manual and rebuild the carb yourself. It's not hard and you only need a manual and common tools. A can of carburetor cleaner and can of compressed air from a computer shop can be used to clean out the carb once it's disassembled.<br />You can get an aftermarket manual from Iboats, or borrow one from your local library. The original factory manual is technically superior, but more expensive. You can get reprints from the following places:<br />TheOutboardWizard<br />Mastertech<br />Marine Engine<br />Ken Cook <br />The manual will pay for itself after your first repair.<br /><br />By the way, the FD-15 is a 1961, 22.0CID engine. It's a very good design that was used for years. In the late 60's they tuned it out to make 20 and 25hp. In the early to mid fifies, it was a 15hp.<br /><br />And welcome to Iboats!
 
Joined
Aug 9, 2004
Messages
24
Re: johnson 18hp will not idle

thank you for the info..i did notice when i choked it it ran better...ill try that....thank you for all your help
 
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