1997 40hp 3 cylinder Yamaha

[tiggerwoods]

My motor idles smooth but spits air only on idle. Just had carb work done and don't believe it's that. Can anyone make a suggestion on what to look at next.

[Charlie206]

Define spitting air a little better. Does it sound like a cough or sneeze?

[DiawaKid]

Was it running good before the carbs were rebuilt? Have you done compression check, new plugs, new gas filter? Do you know if all 3 carb floats were replaced also, they have a tendacy to leak over time. worked on one a while back that had 2 bad floats because the mechanic did not replace them all on rebuilds.

[tiggerwoods]

More like a sneeze

[tiggerwoods]

Ill have to check, but I believe they rebuilt all three. It was spilling gas like crazy before. No new plugs or filter this year, but plugs were replaced last year. Not sure when the filter was replaced.

[Charlie206]

Known as a lean sneeze. The air screws are a little "tight" and the engine is running lean. It is not good for the engine, take it back to whoever did the work or better yet to someone who knows what they are doing and get the air adjusted correctly to the carbs.

[tiggerwoods]

Thanks Charlie206, will do.

[case&cam]

I have 89 yamaha 40hp precision blend on a 147 falcon stick steer (my panfish fish) rig, the issue with the floats that (daiwakid) pointed out is correct! I just had all 3 carbs kits done on mine and 2 weeks later it didnt wanna idle smooth, so took carbs off an the float on bottom carb had filled up with gas, put on a new float and 3 weeks later it done it again, the same carb. So im on my 3rd float and as my mech told me that they use to send new floats with rebuild kits but now they dont so it just so happen my tech had some laying around from over the years. I couldnt believe the same carb done it twice within a months time!

[jethro1]

I have 89 yamaha 40hp precision blend on a 147 falcon stick steer (my panfish fish) rig, the issue with the floats that (daiwakid) pointed out is correct! I just had all 3 carbs kits done on mine and 2 weeks later it didnt wanna idle smooth, so took carbs off an the float on bottom carb had filled up with gas, put on a new float and 3 weeks later it done it again, the same carb. So im on my 3rd float and as my mech told me that they use to send new floats with rebuild kits but now they dont so it just so happen my tech had some laying around from over the years. I couldnt believe the same carb done it twice within a months time!

Your mechanic needs to brush up on what is included in a Yam carburetor kit. Assuming that he is buying a Yam kit and not a kit for a Yam from some aftermarket source.

2014 Yamaha MRP Catalog