yamaha efi resistor caps

[bernieb]

Just replaced two orange screw on resistor caps on spark plugs but can anybody explain the reason for the resistor being there ? and if a cap shows to be "open" meaning no continutity ,can't the high ark just jump the gap ,so to speak? when one goes bad how does that affect performance? what are the symptons at idle ? does it affect gas mileage ? I haven't tried the engine since the new caps went in ,but i've been having problems with erratic rpm idlling like dancing between 400 to 700 and slow speed in gear stalling,not always but most of the time, and on the hose at home the tach stays around 700 rpm but only runs for 10 minutes then i shut the engine down.The engine is a 2001 250hp turz efi.

 

[JB]

Re: yamaha efi resistor caps

Yammy Troubles and Repair.

 

[rodbolt]

Re: yamaha efi resistor caps

the cap does two functions, one is to aid in developing the spark and two is to reduce the EMI(electrical noise).<br /> the symptoms can be all of the above and then some.<br /> your symptoms also describe a bad low pressure fuel pump.<br />carefully check them,<br /> they blow up a lot of good motors.<br /> the ign system is capeable of about 30Kv if nessasary but if all is normal at idle you will only see about 5-7Kv.<br />which is why a Kv tester is so handy, a cyl with a fouled plug (or no compression) will normally show less than 2 Kv. will show about the same if there is no fuel in that cyl. a worn plug or a cyl with excessive combustion pressures will normally show 3-5Kv higher than the rest of the plugs.<br />but that engine is trying to tell you its sick, fix it or instead of a motor Dr you will need a motor mortician.<br />you could also have a dirty or defective O2 sensor. that can pop a piston as well.<br />its time for some corrective maint, its not hard but REQUIRES a certain amount of test equipment and a service manual

 

[bernieb]

Re: yamaha efi resistor caps

The low pressure pumps are new along with the sparkplugs ,so i will clean the o2 sensor next and see what happens . This two stroke engine runs great at wot, but i do want to take care of this idle problem so thanks for your input and will post on the outcome. HAHA you are a motor doctor and you sure in hell would make a bum mortician in a white shirt .I think that teaching job is right up your ally but be sure to teach here. bernie

 

[rodbolt]

Re: yamaha efi resistor caps

bernie<br /> a cleaning is a teat on a boar hog without a testing when your done.<br /> aint but one way to test.<br /> I prefer to be a motor Dr, the mortician gig is dismall.<br />you wont belive how tough it is to tell Joe Blow avg customer his motor is popped.<br /> avg joe Blow cant afford the minimum payments on his credit cards,house and truck payments and I am gonna slap him with another 4000?<br /><br /> thats why I hammer PREVENTATIVE maint over CORRECTIVE maint.<br /><br /> yesw I want to teach cause my bones are rebelling about this daily wrenching.<br /> yes I do get blunt, about that I am sorry.<br /> however it does not rectify the fact that if your motor does not perfom as designed its broke.<br /><br /> do you have a trusted dealership that will let you borrow the test harnes's? and do you own a DVM?

 

[bernieb]

Re: yamaha efi resistor caps

Yes,i do have a dvm but will order the test harness and will do the test.In your line of business repairing these computer controled genies for the "little guy" can be a chore especially with parts so high but this "little guy" respects your knowledge .....so be blunt it may save my life and others 30 miles from shore. will post the results.thanks