Air Leak or Carb Problem?

Have a 70 HP 1991 Evinrude that previously would idle fine but would not pick up speed when in gear. Replaced fuel pump and now engine will not idle or run unless the choke is continuously pressed. I've looked at previous posts and symptoms point to either a air leak in the fuel line or carb rebuild. Is there anyway to confirm which problem I might have? I've looked over all the connections in the fuel line and pump and unless a very small leak would cause this problem, didn't see anything obvious. Just want to make sure I do in fact have a carb problem before taking them apart.

Re: Air Leak or Carb Problem?

You may have had carb problems all along. What led up to the problem? Did it ever run right and has it sat for a while without use? I would pull the carbs, clean and rebuild them...It's not bad on that motor. I have the same one...

Re: Air Leak or Carb Problem?

Motor did sit for almost a year but I do make a habit of burning up all the gas and draining the gas from the carbs before putting boat up for the winter. You say they are not bad to clean and rebuild. What exactly is the process? Remove bowl, clean bowl, put bowl back? Guessing there is more to it than that. I have cleaned carbs on a lawnmower before but that is about as high tech as I have gotten.

Re: Air Leak or Carb Problem?

lawn mower and outboard almost the same. need rebuild kits, and the do a link and sink, you need to original omc manual for that. kencooke.com

Re: Air Leak or Carb Problem?

What is "link and sink"? Guessing "original omc manual" is not my owners manual but the service manual right?

Re: Air Leak or Carb Problem?

Yep, you will need a service manual to guide you through it. Basically, remove the air box, remove the linkage and fuel hoses, remove the carbs, disassemble and clean. Use new kits to renew parts inside. Mostly a matter of unbolting and bolting back on. If you take pics and mark where the linkage is when you remove it and install it in the same position, a lync and sync should not be necessary. Lync and sync is basically adjusting the carb linkage to the timing linkage so that all advance in unison at the proper time..You can get Manuals at the dealer or at the link below. If you get stuck or have questions, there's plenty of help right here...

http://www.iboats.com/mall/index.cgi?category_id=251023&view_id=251023&search_type=category ] Click Here [/url]