C85txrt Stator and timer base resistance test

[wigginbgtm]

I have the afore mentioned motor and want to test the stator and timer base but I dont have the book that gives the readings and which wires should test what, anybody have the tech manual laying around? Thanks

 

[rodbolt]

Re: C85txrt Stator and timer base resistance test

why?

 

[wigginbgtm]

Re: C85txrt Stator and timer base resistance test

This motor runs perfectly above 1500 rpms, below it has an obvious miss, that has been unaffected by cleaning the carbs. Ive replaced the plugs as well. I pulled the plug wires one at a time and checked the spark, which seemed to be, not really eratic but not uniform spark, so I figured Id check the stator and timer base to see if they are within specs (resistance). Im about to just order the manual and be done with it, I figured it would be worth an ask.

 

[wigginbgtm]

Re: C85txrt Stator and timer base resistance test

I bought the online seloc catalog and did the test this morning the low speed charge coil was bad, so we are replacing a $300 stator. Ive never seen one of these go bad.

 

[rodbolt]

Re: C85txrt Stator and timer base resistance test

are you using the DVA output voltage test both loaded and unloaded or a resistance check?
its incredibly odd for a low speed charge coil failure to actually start.

 

[wigginbgtm]

Re: C85txrt Stator and timer base resistance test

resistance test, yes I know Ive been messing with this for 2 weeks. It ran great except low speeds up to about 1500 rpms I had alot of water ect in the fuel tank and I kept thinking I was missing something in the carbs since I couldnt get it to idle right, but once I got the book the low speed coil tested bad, the high side tested fine.

 

[rodbolt]

Re: C85txrt Stator and timer base resistance test

beg buy borrow or steal a meter that either reads peak voltage or a meter with a DVA adapter and test the low speed charge coil output and the CDI output.
peak reading is not RMS.
what kind of resistance numbers are you getting anyway.
its not that uncommon as not all meters have the same input impedance.

 

[wigginbgtm]

Re: C85txrt Stator and timer base resistance test

the high side read 150 ohms and the low side read 1.899 or something in that neighborhood, I rechecked it several times because when I ordered the stator they said they dont sell many, this I believe . Ive never replaced an electronic component on any yamaha or any other japanese outboard or motorcycle either one, ( Ive owner several of both).

 

[rodbolt]

Re: C85txrt Stator and timer base resistance test

double check your meter.
look to see if its 1.99 K ohms.
the spec is about 1050 ohms which is 1.05 K ohms.
most meters,if digital, will auto scale and display a small K.
at 1.8 ohms you wont generate enough voltage to start most likly.
at 1.8K ohms ill buy the reading.

 

[wigginbgtm]

Re: C85txrt Stator and timer base resistance test

its not that its not generating enough to run it, it just did not fall within the range the book specified. I really didnt question the readings. Ive done this test many times and like I said the fact that the low speed coil tested bad, it kinda made sense, since I couldnt find any other problems with the fuel system

 

[rodbolt]

Re: C85txrt Stator and timer base resistance test

I just dont buy your results, however your looking at it and I am looking at a monitor.
resistance readings are **** poor at best, I wish to know voltage output both loaded and unloaded to accuratly troubleshoot anything.
and it takes a DVA or peak reading meter to find it.

 

[wigginbgtm]

Re: C85txrt Stator and timer base resistance test

I have to assume that a resistance test has to have some merit or they wouldnt have bothered to include it in the tech manual. So tell me what would you think it is then? Going to be hard to trouble shoot from NC is it not? I thought asking questions on this forum would be helpful, I also thought posting my results might be helpful to others. I have found after working on outboards for years there are no absolutes when it comes to outboards and when I take readings that dont fall within the ranges specified in the tech manual I dont question the results, but I do appreciate you doing that for me. Maybe after Ive sat behind my computer and posted 15000 messages Ill be an expert.

 

[rodbolt]

Re: C85txrt Stator and timer base resistance test

a tech without a peak reading meter ??
a good meter can be had for 111 dollars or so.merc part# 91-99750A1.
its analog so you can spot intermittants that the digital cannot. the draw back is its polarity sensitive.
one of my digital meters, in auto range, scales about 1000 ohms.
so if I tested a circuit with a spec of 1200 ohms my meter will display 1.200 but with a very small K symbol alerting me its Kilo Ohms and to multiply my scale by 1000.
anyway, I actually have about 30 years at this, was an FC,advanced electronics field, in the USN for 6 years.
have training certs from Volvo,Mercruiser<honda,suzuki,Tohatsu,mercury,mariner,force and I am currently one of not many certified Yamaha master technicians.
its not uncommon to see resistance readings slightly out of spec and still perform correctly.
it also depends on the spec callout of the meter being used.
imput impedance has a lot to do with it.
the high speed windings on your unit have a call out of 120 Ohms.
your high speed is technically out of spec but you say it still runs well.
all resistance readings are at room temp and plus or minus 20%.
I have seen it to many times especially with Japanese stuff.
sometimes the manual translation simply fails.
but thats why I do a charge coil input voltage test and the CDI output voltage test and I instantly know can the device physically work.

 

[wigginbgtm]

Re: C85txrt Stator and timer base resistance test

Yes I know, we lost everything during Ike and I havent been able to replace it yet, there hasnt been much going on around here since the storm unless you want to swing a hammer. Anyway thank you I do understand the DVA test is more conclusive, but Im working with what Ive got. Your creds are quite impressive I was unaware. What would be your guess then, if you dont mind my asking. I know the carbs are spotless and the reeds are fine and everything else read within specs.

 

[rodbolt]

Re: C85txrt Stator and timer base resistance test

myself I would still lean towards fuel. but if this is a flood recovered motor all bets are off.
thats when I would really chase the DVA specs. rapair sells a DVA adapter that fits most standard DVM's but for your case I would use either one on my CD77 meters or my 91- merc meter .
digital simply wont scale fast enough to catch most intermittant failures.
that 91- meter can be had at most NAPA stores or west marine stores either under the quicksilver brand or the Sierra brand.
the draw back to analog is attention must be paid to meter lead polarity and scale setting.
a pulser coil failing could also affect the engine.
each of the 3 pulsers control 1 ign coil primary.
only good way to test the system is with everything hooked up(loaded) and peak voltage readings for both the CDI charge coil inputs and the pulser coil inputs and the peak ign coil primary voltage while its at the RPM the problem is occuring.
a bad low speed charge coil could affect all cylinders a bad pulser just one.
if all inputs are good and one output is bad look at ign coils and CDI modules.
if you have an analog multimeter you may be able to catch any voltage hiccups with it.
your readings will be mostly meaningless but what you would be looking for is a steady needle.
will read low but should remain steady on both the inputs and the output.
the inputs are technically an AC voltage and the CDI output is technically a DC output.
however due to the solid state devices and the very rapid rise and fall times of the CDI discharge it will act like a DC input when loaded and an AC output when loaded.
thats why we are looking for a Peak voltage and not an average or an RMS.
yes I have had to do testing in Venezuela this way where a peak reading meter just wasnt in the country, however I do have a thorough understanding of how a CDI ign system works.
but in VE not only is the part not going to be avalible it may take several weeks and a lot of extra expense to obtain it so I had to be right.
most my work here in the states is contract, if I tell the marina this engine needs a module,a stator or a high pressure pump and I am wrong guess who buys that part?

 

[parrfive]

Re: C85txrt Stator and timer base resistance test

Dont really want in on this but have you checked your fuel pump? Sounds like a blown diaphragm to me. Or at least one leaking somewhat. Just a though.