How JustAnswer Works:
  • Ask an Expert
    Experts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional Answer
    Via email, text message, or notification as you wait on our site. Ask follow up questions if you need to.
  • 100% Satisfaction Guarantee
    Rate the answer you receive.
Ask Joe Your Own Question
Joe
Joe, Marine Mechanic
Category: Small Engine
Satisfied Customers: 7251
Experience:  ASE, electronics, Marine inboards and electronics, automotive drivability, all around repair tech,
20508815
Type Your Small Engine Question Here...
Joe is online now
A new question is answered every 9 seconds

I havea model 351447 that the front cylinder is running lean

Customer Question

I havea model 351447 that the front cylinder is running lean on. I HAVE ENLARGED THE JET FOR THAT CYLINDER BUT THE PLUG IS STILL BURNING WHITE. dO I HAVE TO DRILL SOME AIR JET TO GET MORE GAS TO THAT CYLINDER? tHIS IS A TWO BARREL DOWN DRAFT CARB.
Submitted: 1 year ago.
Category: Small Engine
Expert:  Curtis B. replied 1 year ago.

Welcome to JUST ANSWER small engines, let me try to help you !! I don't know it all, but maybe together we can get you a satisfactory answer!

Expert:  Curtis B. replied 1 year ago.

Twin cylinder OHV engine. You say it is running white on one cylinder? What does the other cylinder plug look like? Have you ran a cylinder test on the engine? Loosen the spark plug wires, and with it idling , remove one wire at a time, engine should continue to run, if it dies when wire is removed, the opposite cylinder is the one not firing.

Customer: replied 1 year ago.
I rean a compressioin check on both cylinders and they are ok. I had the carbureator disassembled, vatted.blown out and reassembled. no help. I sprayed eather around the base of the carb and the intake to engine connection no leak. The motor is run at 4900 RPM and the front cylinder runs lean. Checked the plugs and the back plug is choclate and the front one is white. I installed a larger main jet in the barrel for the front cylinder and the head temp is still running 450 degrees. The motor is not skipping just have a cylinder running lean. DO I NEED TO ***** AIR BLEEDS ON THE CARB. I know this is a tough Questrion and its going to take a carb specialist who is familiar with this carb to answqer it.the carb is a briggs and Stratton 2 barrel.
Expert:  Curtis B. replied 1 year ago.

Have you ran cylinder test? Just because it has compression , does not mean the cylinder is firing, My thought the cylinder that is chocolate is not firing. With Briggs twin, I would be checking the rockers and pushrods. I think drilling jet in carb is wrong move.

Customer: replied 1 year ago.
ENGINE IS RUNNING FINE. BOTH CYLINDERS ARE FIRING. CHOCOLATE IS THE COLOR THE PLUG IS SUPPOSED TO BE PLEASE TURN THIS QUESTION OVER TO A MECHANIC OR GIVE ME MY MONEY BACK. I HAVE BEEN A SMALL ENGINE MECHANICK FOR 35 YEARS AND I HAVE CHECKED THE ROCKER ARMS AND PUSHRODS AS WELL AS THE CAM LOBES.
Expert:  Curtis B. replied 1 year ago.

You could have worked for me. I will opt out and let you find a real mechanic. Have a great day. Please do NOT respond to me or it will lock the question to me!

Customer: replied 1 year ago.
give me a new tech. please
Expert:  Joe replied 1 year ago.

Hello,

Thank you for allowing me to assist you, my name is ***** ***** I will be happy to assist you with your concern today.

I would like for you to run a leak down test, much different from a compression test as if you have a leak not shown on compression reading it could cause a lean running condition on that cylinder, common lean issue.

You stated carb was vatted, I assume you installed a full new rebuild kit?

If the engine is factory spec and you are running an correct application carb then you should not be needing to change any jets or anything else.

Next thought would be an actual problem with the carb requiring replacement of the carb, but you should also check spark with a spark tester watching as it jumps the gap and checking if weak because it may be firing but not correctly (and chances are it is not spark related as you stated it is running lean not rich) so my thoughts will be nothing related to spark.

Thank you!
- Joe

Please rate my answer when ready. Bonuses are appreciated.
If for any reason you are not satisfied please reply back to me for further assistance to which I will be glad to help you. If you have any problems for any reason please reply back and let me know.
Thanks again for using justanswer and have a great day!

If you need any further assistance you can reply back at any time for my help.
I'd be happy to answer any other questions you have even if not related.

Customer: replied 1 year ago.
leak down is 2% on that cylinder and spark is strong.