Fuel starving engine

[A23]

Hello everyone, I have a two year old Johnson 15 hp longshaft, used on my sailboat. I use it only to push the boat in and out of the harbor. Total hours probably do not exceed 25 at this time.<br />My problem is fuel starvation, which startd at the end of the season last year. <br />When I start the engine I use the primer bulb to develop a good pressure. Engine starts with one pull. It will idle for a few minutes and die. When I go to the primer bulb it is empty. Here is the confusing part, if I run it at full throttle it will run all day. As soon as I drop back to low idle, it will die within a minute or so.<br />I spoke with the store I bought it from, and the service manager indicated that the fuel pump is good, but has no idea what is happening.<br />Could I have a bad check valve in the primer bulb, or possibly a bad fuel connector letting air in?<br />Has anyone else had this problem.<br />Thanks

 

[DJ]

Re: Fuel starving engine

A23,<br /><br />Both of you assumptions are good ones. Both are easy and inexpensive to remedy.<br /><br />Since you mention that it runs OK at speeds above idle, we can rule out fuel starvation due to improper venting, etc.<br /><br />If those two items do not fix your concern, you may have clogged low speed jets in the carburetor. Does it help if you try to pull the choke out slightly?

 

[A23]

Re: Fuel starving engine

A follow up for anyone with a similar problem. I replaced the primer bulb and fuel coupling and still had the problem where the motor would die at idle. I then went below and looked at the fuel coupling to the tank, and it was loose. I replaced it and the motor now runs fine.