More Fuel Problems

[rodbolt17]

how ya figgure???
spark is spark is spark.
voltage potential builds until its sufficient to arc the plug gap under compression.
same as merc jonnyrude tohatsu,suzuki and 90% of the rest of ADI/CDI spark ign engines.
may I suggest doing a google search on ADI and CDI ign system theory.
your engines ign system can be divided into two subsystems.
ign producing,pulser coils,stator CDI charge coils,fly wheel magnets the CDI and the ign coils.
the second half is ign controling,knock sensor,TPS sensor crankshaft position sensor engine coolent temp sensor and the micro-processor.
try using the A&B bypass and bypass the ECU.
test spark using a tester with a 7/16ths gap.
if its weak look at the CDI charge coil input.

[BigNiner19]

how ya figgure???
spark is spark is spark.
voltage potential builds until its sufficient to arc the plug gap under compression.
same as merc jonnyrude tohatsu,suzuki and 90% of the rest of ADI/CDI spark ign engines.
may I suggest doing a google search on ADI and CDI ign system theory.
your engines ign system can be divided into two subsystems.
ign producing,pulser coils,stator CDI charge coils,fly wheel magnets the CDI and the ign coils.
the second half is ign controling,knock sensor,TPS sensor crankshaft position sensor engine coolent temp sensor and the micro-processor.
try using the A&B bypass and bypass the ECU.
test spark using a tester with a 7/16ths gap.
if its weak look at the CDI charge coil input.

All the outputs from the CDI were within the manual specs. I did not try and bypass the ECU because I still think its a fuel problem.

I am out of ideas for trouble shooting. Only thing I can do is continue to clean carbs, but there is just no way they aren't clean now. One of those floats or needles gets stuck and floods the motor or something.

Cory

[99yam40]

what were the readings you got going out to the coils and what did you read that voltage with?
Did you measure the inputs to the CDI also?

Did you follow the troubleshooting steps in the manual or just skip around and test this and that?

give all the details not just "within specs"

Rodbolt is a yamaha master tech and this is the best way to get info from him and anyone else.

If you have the jets in the wrong places you will be running lean on some cylinders and rich on others

[BigNiner19]

Okay, I wrote everything down as I went through step by step in the manual. I will post back when I get home this evening.

[rodbolt17]

how the testing starts.
test compression, test spark fix the fuel system.
if compression is within 10 psi bank to bank and the spark on all 6 will jump a 7/16ths gap your typically fighting fuel
mixing the jets WONT disallow starting.
you either dont have fuel in the bowls or the choke is not functioning.
you most likly did not get the pilot fuel circuits clean as well.

[BigNiner19]

how the testing starts.
test compression, test spark fix the fuel system.
if compression is within 10 psi bank to bank and the spark on all 6 will jump a 7/16ths gap your typically fighting fuel
mixing the jets WONT disallow starting.
you either dont have fuel in the bowls or the choke is not functioning.
you most likly did not get the pilot fuel circuits clean as well.

I'm going to have to say that you are correct, but I still think I could have a needle/float issue.

I have the compression numbers written down and the CDI inputs/outputs all written down. Compression if I remember correctly was 125 PSI on 5 cylinders and 120 on #6

There is definitely fuel in the bowls because when i take the carbs off fuel comes dumping out of them. The choke...you've got me on that one. It has those little flappers on them and I'll shut them to try and fire it up and Ill open them, it makes no difference in trying to get it started at this point.

Cory

[BigNiner19]

Not finding all my notes, but here is some of it.

Primary Voltage - 86 #1 Coil
113 #2 Coil

Low Speed Charge Coil - 103 Volts
High Speed Charge Coil - 18 Volts

Compression #'s

#1 - 120 #2 - 125
#3 - 125 #4 - 125
#5 - 125 #6 - 120

[rodbolt17]

what kind of meter and adapter are you using for voltage checks?
is it peak reading or true RMS ?

[BigNiner19]

what kind of meter and adapter are you using for voltage checks?
is it peak reading or true RMS ?

Peak reading with a DVA meter

[BigNiner19]

Could this be a stuck float? Getting caught up on the bowl? OR possibly just worn out floats/needles and I'm trying to re-use them?

I'm out of guesses, and without buying parts and throwing them on, I dont know where else to troubleshoot.

Cory

[200090tlry]

Maybe add little oil in gas tank

Depending on your motor it might be ok. Maybe that lube will help keep needle from sticking. Ethanol could be non compatible to your needles tip? Your pilot screws how far out are they and if they are set like manual states maybe 1/4 in might help run and see how it idles now. Your motor I think has different settings for carb unlike my simple 3cyl. I just reread your first post bulb felt like sucking air. Gotta fix that first before trying to diagnose anything else. Mine gets hard as rock now with new attwood universal bulb kit,fuel pump diaphram kit. The fuel quick connect at motor check to see if rubber oring is installed correct, check your parts diagram. Boat I just purchased was missing this silly oring and allowed fuel to drip down if tilted sideways. Added the oring and now seems sealed up better. Now mind you this was serviced by Marine shop and ive been redoing all there work. Heck if you were in my neck woods id have a look at motor and figure this out. On my mercury motor I suspected check valves attached to block was messing up my idle because it also got the stalls after 2 minutes running. Could have been that or needles rubber sticking shutting off fuel. Im running semi syn oil now because ive had great results on previous Mercury, pennzoil semi mixed in tank. Yamaha is oil injected but I might change that soon, I added little oil in tank maybe 125to1. I figure the oil might be good for needles,pivots for floats.

[BigNiner19]

I appreciate your response. The bulb and fuel hose have been replaced. Its a good possibility that I had multiple problems and have fixed some, but not all. I am running off a portable tank now that I know has clean fresh gas in it. I also know my fuel lines are brand new with a new bulb and brand new filter motor side, going through 2 brand new fuel pumps into 3 carbs that I have cleaned thoroughly, but not replaced with a carb rebuild kit yet ( I did however just buy one of those too for $124). I have not replaced the quick disconnect, it appears to be fine, plus I know fuel is getting to the carbs!

SO thats where I'm currently at. I've got to figure that this is a needle/float issue not allowing fuel (even though in the bowl) not to get into the carb itself to burn. I'm not sure why as when I take the carbs apart, everything seems to be freely moving and clean, but this whole process has not been easy, so why would it get easy there.

Cory

[GW267000]

For what it’s worth, my buddy had a problem much the same as what you are going thru. When engine was running bad you could restrict air flow into carbs by covering part of intakes (more gas to air mix) to make the motor run. Until he rebuilt, not just clean, he was able to correct problem