Motor only runs on choke

J

J Osborne

Recruit
Joined
May 19, 2005
Messages
2
I have a '76 Evinrude 85hp motor It only runs on choke and I have tested everything I can think of like the fuel pump, cleaned out carb jets, checked linkage. Can anyone tell me what's wrong?
 
W

Walker

Captain
Joined
Jun 15, 2002
Messages
3,085
Re: Motor only runs on choke

Clean the carbs again. Tear them down completely, remove all jets and soak in a suitable carb cleaner for an hour. Finish the cleaning job with aerosol carb cleaner and compressed air and make sure each and every passageway, no matter how small, is clean and compressed air will flow thru it. Reassembele with new carbs kits.
 
P

phatmanmike

Captain
Joined
Oct 24, 2003
Messages
3,869
Re: Motor only runs on choke

if it only runs with engine choked, it has an air leak and is normally getting too much air, so when you choke it, its cutting out some of that extra airflow.<br /><br />im not really sure whay cleaning the carbs will do about this?
 
W

Walker

Captain
Joined
Jun 15, 2002
Messages
3,085
Re: Motor only runs on choke

Clogged up idle circuits and /or intermediate circuits will not allow fuel to flow thru those parts of the carbs. Choking the carbs on a 76 motor closes the choke butterflies and the vacumn pulls fuel up thru the main jets.
 
JB

JB

Honorary Moderator Emeritus
Joined
Mar 25, 2001
Messages
45,907
Re: Motor only runs on choke

There are four sets of jets on that engine, but only one fuel supply. What do you suppose the odds are of all four sets of jets plugging up at the same time?<br /><br />I think myoutboards offers a good probable suspect.
 
R

rdh2059

Seaman
Joined
May 16, 2005
Messages
55
Re: Motor only runs on choke

One more thing to make sure about is the fuel pump. I was having this same problem with a 1969 55hp evinrude and it ended up being a weak fuel pump not providing enough fuel. It idled great and would go to about 1500 RPM, before it started dropping RPMs back to about 1000. Replaced fuel pump and its now working nominally.<br /><br />Rick
 
K

karrick

Petty Officer 1st Class
Joined
Oct 12, 2003
Messages
259
Re: Motor only runs on choke

Check to make sure there is no fuel restriction in the lines and primer bulb. My engine did that one time out, and I held the primer bulb in the vertical position instead of the horizontal and it got fuel and ran without the choke. something in the bulb was cutting off flow.<br /><br />Good Luck<br />K
 
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