2003 yamaha 40tlrc idle issue.

[TBTech24]

engine was serviced 3mths ago. carbs where cleaned twice looked good both times. Motor fires up and will run above 1300 rpm, but anything below it lean pops and coughs out. pulled the plugs which where brand new and they are black and soaked. It has gotton worse in only two trips to the point where docking and trailer loading is a toss up. compression is good 125 across the board. spark is strong at 7/16 gap. i dont have the timing procedure to make sure the timing is correct. Im kinda confused because it sounds like a lean pop but plugs show fouled rich plugs. im stuck...

 

[handle]

Re: 2003 yamaha 40tlrc idle issue.

I assume if you had the carbs cleaned twice before it was not running well. Is it acting the same as before the cleaning? Usually the carbs would show some signs of debris or deposits if they to be cleaned twice, partially pluged pilot jets or something. With the motor running try to cover the air cleaner and see if the motor revs at all, if so she is running lean on the low end. Back to the carbs. It doesn't take much to plug them up.

 

[99yam40]

Re: 2003 yamaha 40tlrc idle issue.

bad fuel, bad fuel pump,timing off, bad cleaning job, not doing the link and sync after reinstalling carbs are some of the things that could be a problem

 

[TBTech24]

Re: 2003 yamaha 40tlrc idle issue.

right it wasnt running well. harder to start and keep running. the carbs had some ethanol buildup in the inlets and the bottom of the bowl. soaked and cleaned new float needles. ran much better started right up idle nicely. then after a while it started the lean pop every once in a while. it was time for a service then anyways so changed the fuel filters plugs impeller oils the whole nine. since i was into the motor i decided to pull the carbs and clean them again since it would die on me . they looked godd vut soaked and cleaned them again. used the same new needles as the first clening. its been fresh fuel just uae a six gallon tank.butterflies are shut almost all the way closed cam is set. the only thing i havent checked was the timing procedure.

 

[99yam40]

Re: 2003 yamaha 40tlrc idle issue.

Apparently you do not have a Yamaha service manual for your motor, pick one up.

Not sure what cam you are talking about unless this is a 4 stroke

If it has a lean sneeze your carbs need more attention or you have a vacuum leak some where

 

[handle]

Re: 2003 yamaha 40tlrc idle issue.

Are you running a fuel seperator? Might want to cut open a small piece of fuel line and look for deterioration. The smallest particals will plug those carbs. There is also a in-line fuel filter that can be replaced.

 

[TBTech24]

Re: 2003 yamaha 40tlrc idle issue.

I don't have the book. Or a fuel separator. When I pull the fuel pump off the block and squeeze the ball the pump leaks where the mounting bolts go through it. that's what the problem seems to be. Because of ho soaked the cylinders are. But.where the.whole in the fuel pump and the whole in the.crankcase seems dry

 

[99yam40]

Re: 2003 yamaha 40tlrc idle issue.

you need to put bolts and nuts in those to seal it up properly while checking that way, if it is not coming out the pulse port then it is not the problem.