1988 Yamaha 150ETXG w/ 3 left side spark on welfare

[Crowsnest17]

Bought new in '88 this has been well maintained and has been good to us but now we have a perplexing problem and are not near a reliable place to fix it. This gets used about a month or so a year and then sits the rest of the year. I've broken down and cleaned the carbs several times in the past few weeks but can just get the 22' Sisu up to plane and tops out at 3,000 RPM WOT. New fuel, filters, plugs. Everyone said it was carbs so foolishly kept working on them and fuel until discovering that there is no spark from the left 3 plugs even after switching plugs. With a fluke 73 the 4 stator charge wires ohm meter well within specs while hot. Compression is good and the same on all. The coils ohms meter a little high but all the same. The pulser coils appear to ohm meter within specs. I don't have a peak voltage adapter for the meter and have not done any conclusive testing on the CDI. It seems like one of the two condensers within the CDI could knock out one side of the spark like that. Two kids in college eliminate the new motor option. I have a chance to have a friend fly down with a part but which part is the question. Any suggestions? Thanks,

 

[rodbolt]

Re: 1988 Yamaha 150ETXG w/ 3 left side spark on welfare

you really really need a peak reading meter.
however.
can you do a forum search on a mome made spark tester and make one?
if you can I can tell you how to cheat the system some but it must be done with all 6 plugs hooked to a spark tester,for loading, with a 7/16th gap and the plugs out.

 

[Crowsnest17]

Re: 1988 Yamaha 150ETXG w/ 3 left side spark on welfare

Thanks for the reply Rodbolt, I drove up to the nearest town today and they had no idea what I was talking about when I asked about a DVA or peak voltage adapter. I like to make things so I will look online for a home made spark tester. Any suggestions for a good design? We are very limited down here (one stop light 20 miles away, (why we try to get here)) for parts but a friend is coming down in a week and he might be able to bring something in if I can order it online and it gets to him soon enough. Thanks, Peter

 

[99yam40]

Re: 1988 Yamaha 150ETXG w/ 3 left side spark on welfare

Here is a DVA adapter to use with your meter I found on the forums that worked for me that you can make if you can find the parts


Seems like I have seen a spark tester made from a wood board, nails, and wire.
Like he said do a forum search for homemade spark tester.

 

[Crowsnest17]

Re: 1988 Yamaha 150ETXG w/ 3 left side spark on welfare

Here is a DVA adapter to use with your meter I found on the forums that worked for me that you can make if you can find the parts


Seems like I have seen a spark tester made from a wood board, nails, and wire.
Like he said do a forum search for homemade spark tester.

Thanks 99yam40, There is no radio shack on the island and UPS uses coconuts and strings so I might find the parts you kindly suggested but probably not before I have to return to the states and fixing some leaking roofs. The spark tester idea of Rodbolts might be more expedient and yes I am familiar with nails and boards and can whittle up something that tests sparking ability if I knew what the goal was? I'll look for a design on google. They need to be all fired through one gap?

 

[Crowsnest17]

Re: 1988 Yamaha 150ETXG w/ 3 left side spark on welfare

Yes Rodbolt, a search on the forum found a thread for homemade spark testers and that is well within my abilities, even a six sided one. So if I knock one together tomorrow what would I be able to determine with it? Other than the fact that there is no spark on the left side and the spark on the right side is a little weak to my unprofessional eye?

 

[Crowsnest17]

Re: 1988 Yamaha 150ETXG w/ 3 left side spark on welfare

you really really need a peak reading meter.
however.
can you do a forum search on a mome made spark tester and make one?
if you can I can tell you how to cheat the system some but it must be done with all 6 plugs hooked to a spark tester,for loading, with a 7/16th gap and the plugs out.

I can make a simple spark tester with some nails and a board. What would the next step be?

 

[rodbolt]

Re: 1988 Yamaha 150ETXG w/ 3 left side spark on welfare

next step will be to hook up all six leads to the tester with a seven sixteenths gap,crank the engine and observe spark.
if one bank sparks and the other does not use the ac voltage scale and test the CDI outputs bank to bank.
if you lose a pulser coil youwill lose a cylinder on each bank.
the charge coil on that motor charge the capacitors for both banks.