Low power/idle RPM- running rough

[Capt. Lowtide]

an inside joke.
once you buy the service manual and quit splatter gunning I may add advice.
the pulser coils are not mounted on the stator assy and cannot be seen until the flywheel is removed.
for spark triggering there are 2 pulser coils that control 1&4 and 3&6.
2&5 are synthesized based on crankshaft position sensor input.
lose the CPS and you lose spark on 2 cylinders, lose a pulser and you lose spark on 4 cylinders as the ECU will go into default.
ya simply are wasting time pulling plug wires.
for capacitor(spark generation) there are two charge coils, one high speed and one low speed.
its a dirt simple setup.
but ya have to have some equipment, some knowledge of how and why it works and a manual of some kind.

rodbolt are you Ish? Sorry inside joke, thanks for dangling the carrot. Looks like my free advice has been cashed in... much appreciated while it lasted.

Probably wasted my time with an inexpensive spark tester light, but hooked one up anyway. No spark on the starboard bank and seemingly weak spark on the bottom port side (took allot of cranking to get the bulb going.)

Checked with local dealers today and no one has a manual for sale, not even a Seloc. Does it really take 3-5 days for a download from yamahapubs.com?

[99yam40]

Take the manual number you found on the Yamaha site and punch it into your web search engine to see what you come up with.You may find a site that will allow you to down load instead of waiting for snail mail

[Tucker]

It was a web thing about some guy wanting a tech to replace his car alternator to fix his problems without trouble shooting and saying it would fix the problem he had. don't worry about it. Rod was just being funny

"And don't piss on my leg and tell me it's raining" Sorry, couldn't help it...

[99yam40]

rodbolt are you Ish? Sorry inside joke, thanks for dangling the carrot. Looks like my free advice has been cashed in... much appreciated while it lasted.

Probably wasted my time with an inexpensive spark tester light, but hooked one up anyway. No spark on the starboard bank and seemingly weak spark on the bottom port side (took allot of cranking to get the bulb going.)

Checked with local dealers today and no one has a manual for sale, not even a Seloc. Does it really take 3-5 days for a download from yamahapubs.com?

If you want to do some electrical trouble shooting you will need a Peak reading voltmeter made for these ignition systems or a DVA adapter and a regular meter , so start looking for those also if you do not have them already

[Tucker]

rodbolt are you Ish? Sorry inside joke, thanks for dangling the carrot. Looks like my free advice has been cashed in... much appreciated while it lasted.

Probably wasted my time with an inexpensive spark tester light, but hooked one up anyway. No spark on the starboard bank and seemingly weak spark on the bottom port side (took allot of cranking to get the bulb going.)

Checked with local dealers today and no one has a manual for sale, not even a Seloc. Does it really take 3-5 days for a download from yamahapubs.com?

Low,
With the money you save by getting expert advice from these guys you should spring for the real shop manual from Yamaha. The good folks at boats.net can hook you up. Yea, it's close to $100 but it's better than the knock-offs.

[rodbolt17]

nope, but without the manual or at least a tuneup spec guide AND a peak reading multimeter you cant do much with the ign system.
I also use a Kv tester to test secondary firing voltage.
use the PEAK reading NOT a true RMS reading meter to test pulser coil output and crank position sensor output and high and low speed charge coil outputs then CDI outputs.
yes its as simple as that.

[Capt. Lowtide]

stator

Had the engine checked out at the Yamaha dealer I mentioned previously, got to watch them run several test. Diagnosis was the stator, short to ground knocking out starboard bank of cylinders. When disconnected the engine ran on all six I've been told.

so, rodbolt was correct in his first diagnosis- alternator, haha

Thanks again for all your assistance here, great forum.

[grahamd7504]

fuel

a long shot, but have you checked the fuel tank breather (is it blocked or restricting flow ) good look, doe,s sound like a fuel issue 100 % may be try a seperate fuel supply (tank to fuel pump ??) hope you beat the problem

[rodbolt17]

wrong.
dissconnect the stator and you instantly lose spark on all six.
try again.
the charging system is TOTALLY seperate from the ign system.
all they share in common is the flywheel and the stator ring.

[Capt. Lowtide]

wrong.
dissconnect the stator and you instantly lose spark on all six.
try again.
the charging system is TOTALLY seperate from the ign system.
all they share in common is the flywheel and the stator ring.

I apologize, in no way do I mean to insult your intelligence. I most likely misunderstood what the tech was telling me over the phone about disconnecting the stator.

The tech told me that they were dumbfounded with the testing results and made a call to a Yamaha tech help line. The standard service manual testing procedures did not identify any common reason for the problem. The Yamaha help line suggested a route of testing that identified a short in the system.

We will all know in the next few days once the stator has been replaced.

Now I imagine you techs with great experience are calling BS, but this is all I have to go on now. As soon as I have a better explanation I will certainly let you guys know.

Thanks again for the input and ideas, much appreciated.

[200090tlry]

Does this model have fuel pump?

If so would not hurt to tighten down little bit or check to see if there loose. Dont over tighten though that's all alum I think. 3 philips,2 10mm bolts. If motor is new I wouldnt worry but if it's really used motor I think it might be fuel issue. Maybe combo issue going on slight weaker spark something and is showing fuel issue more. Also if you read my posts factory set carbs 1 1/2 mine would barely idle at lake needed to put them 1 1/4 and also took fuel enrichment from closed to normal so im not sure which causing lousy idle. Mine never stalled after 2 adjustments. What year is v150? Is this 2stroke or 4stroke? If it's 10 year old motor that sits in elements like Florida or in water id lean even more to fuel.

[rodbolt17]

V150TLRZ
vmax carbed with manually activated choke, 150 HP,trim,20" transom and a 2001 model.
has a high and low speed CDI charge coil windings on the stator to power the CDI.
has 2 pulser coils that control cylinders 1,4,3 and 6.
the CPS controls spark on 2 and 5.
dirt simple system thats been around at least 25 years.
if ya gotta call yamaha to test it ya need to find a real shop.
with a peak reading meter you look at CDI input voltage.
then look at CDI output voltage.
input spec is about 160V cranking,loaded, on the low speed coil and about 55V cranking loaded on the high speed.
the CDI output needs to be within about 10V of the input.
dirt simple.
short one leg of either coil to ground and you get 1/2 the voltage.
open a leg and you get NO voltage.
see how simple this actually is?