replace all Yamaha carbs Chapter 2

[colayn]

Re: replace all Yamaha carbs Chapter 2

will check under those plates again (#26)
I don't remember seeing anything in there, and it was odd because I kept thinking what is this open space for.

As for running wires to the helm, I thought of that but have to dig around and figure out were to make the connections. Like I said I'm learning alot.

In the mean time do you think I can use the boat if I don't run it hard?
Nov. is some of the best fishing we have and I hate to miss it all.

Also you did not comment on spraying fuel into carb at WOT . Is it proof of starvation if it picks up R's ?

 

[rodbolt]

Re: replace all Yamaha carbs Chapter 2

its nice that DonS gigs me just before I get banned.
dang that was funny Don.

 

[rodbolt]

Re: replace all Yamaha carbs Chapter 2

until you find and solve this issue, I would not reccomend ANY running.
and the red dots thing has nothing to do with you .
but yes, I am getting them.

 

[Don S]

Re: replace all Yamaha carbs Chapter 2

its nice that DonS gigs me just before I get banned.
dang that was funny Don.

Now, back to the regularly scheduled original post by colayn.

He alone gets to decide which posts and posters he wants to listen to.

 

[sdsaw]

Re: replace all Yamaha carbs Chapter 2

Okay, I've read through all the posts in this thread.
Is it possible that it is a reed valve problem?

 

[rodbolt]

Re: replace all Yamaha carbs Chapter 2

sdsaw,
possibly, most likly not but definantly in the realm of possibilities.
actually is easy to look at.
reed issues I can usally tell by ear, however I am behind a monitor.
but at least we did not do 3 carbs.
now we just have to help solve the mystery of #5 cyl.

and remember, there is a reason why DonS is the Oracle.
best tech I never met but he is goooooood.
busts me from time to time but nothing I did not deserve.

 

[colayn]

Re: replace all Yamaha carbs Chapter 2

I am tired of thinking about it today. Signing off.
Must confess , outside the question about the reeds, I have no idea what just transpired in the last few post.
Must be an inside thing
Good night to all,

 

[colayn]

Re: replace all Yamaha carbs Chapter 2

OK, it did me well to get away from it awhile. I understand completely what you want me to test rodbolt on the output side of the CDI. B/W wire on my rig.
According to the spec sheet given me in previous post should be peak 130v at cranking, 145v at 1500 rpm

I hope to do that today and try to spray fuel into each carb at WOT.

One question, my DVA meter will read up to 1k vDC , but is it fast enough to read the pulses on the those 6 wires ?

 

[colayn]

Re: replace all Yamaha carbs Chapter 2

40 miles to the lake so let me know if there is any other test I should make while there

 

[99yam40]

Re: replace all Yamaha carbs Chapter 2

So you have a DVA meter or is it just a digital volt,ohm,amp meter?
You need a special peak reading volt meter made just for reading these ignition system voltages. Or a DVA adapter for your regular meter.

Before running 40 miles I would take some readings while on the muffs just to make sure everything looks OK and you know what you are doing and your wiring and meter work properly.

 

[colayn]

Re: replace all Yamaha carbs Chapter 2

Yea, I did a test run on the muffs and found my multi meter is not fast enough for the pulse.
Came back in and reread the entire post and see I missed the part about the DVA.
Trying to borrow or buy one now. (man another hurdle)
one question, don't want to assume anything. I am testing with DC volt correct?
Not AC volt
I really appreciate you guys staying with me thru this long posting.
Thanks,

 

[99yam40]

Re: replace all Yamaha carbs Chapter 2

If you can not find a DVA, look at the next to last post on this thread, it has a pic of a DVA that I ended up building and testing compared to one I borrowed from a shop and it was within a volt or 2 of the store bought one.
http://forums.iboats.com/showthread.php?t=340776
Problem is you have to find the parts to build it with and something to put it in. it all depends on what is available.

Yes the meter should be on DC v

Here is something to read if you have time to kill, it does not have much on Yamaha stuff, just that it is close to Mercury ,but it does give some basics on testing equipment
http://www.outboardparts.com/troubleshooting/printguide.htm

Also you can do a web search for service manuals for your motor and down load some of them for as little a $10. I have not tried them but have read where others were happy with them. Not much money even if you do not like it
I believe your search should be for 1999 P150TLRX LIT-18616-02-01

good luck and happy reading

 

[colayn]

Re: replace all Yamaha carbs Chapter 2

It will be a few days before I have update on the test.
Tried every possible option , both personal and business to obtain/borrow DVA locally and no luck.
Waiting on parts to build one.
99yam40 - thanks for the link in the last post, it is good info.

Gentlemen, Please check in to the thread in a few days. I will need the help.
Thanks,

 

[colayn]

Re: replace all Yamaha carbs Chapter 2

I recieved my Yamaha service manual, LIT-18616-02-01
Will have the DVA tomorrow.

One question : According to a parts diaghram on line my carbs have 2 sizes main jets, one side carb different than the other.
The Yammy service manual only says qty 2, and does not say anything about size.

My question, if I mixed these up and put them in the wrong location would it cause the problems I am having ? (lost 1000 RPM, and surging at high RPM ?)

 

[rodbolt]

Re: replace all Yamaha carbs Chapter 2

most likly, no.
however the parts manual will tell you which size jet went where.

 

[colayn]

Re: replace all Yamaha carbs Chapter 2

also I found I set my floats at 16mm with gasket on, book says set without gasket.
That would be in the direction to reduce flow.
Could this be a problem ?

 

[99yam40]

Re: replace all Yamaha carbs Chapter 2

are you sure that you are not getting enough fuel to all cylinders as you said they told you? If so then test the fuel supply system with a pressure /vacuum gauge.Testing is always better that just guessing on all parts of the motor.
http://forums.iboats.com/showthread.php?t=283363

If not then start from scratch and make sure the compression is good on all cylinders and there is good spark on all too. make sure the timing is doing what it is suppose to at all times especially at the problem rpm along with the spark. If all is well with that then look at the fuel.

It took me about a year to finally figure out a previous owner of my motor apparently drilled out the main jets( trying to make a 50 out of a 40 is my guess) causing it to drop a cylinder at wot but ran OK other than that.
Not sure but I believe your carbs have different size jets in the different ones and if you do not get them where they are suppose to go it could cause problems too much on some and not enough on others. So make sure you know for a fact what the problem is, trusting something someone said for a fact will run you around in circles

Just thought you should read this earlier post again, make sure all jets are in the proper place and your fuel pressure and vacuum are in spec


Reading back through your posts , it looks like the last time it hit 5600 was after the plugs were changed but then dropped 600 after 5 hours.
Have you tried a new set of plugs again? I have found bad plugs before even new ones, but not often.

 

[colayn]

Re: replace all Yamaha carbs Chapter 2

Have not tried new plugs, but they are on my to do list. Want to try some Champion plugs.
Going to the lake tomorrow to try spraying fuel into each carb at WOT.
If I have the DVA will do the CDI output voltage as well.

I want to try some vacuum test on the fuel circuit but haven't looked into it much thus far. Have spent so much money already trying to prevent buying another tool.

 

[rodbolt]

Re: replace all Yamaha carbs Chapter 2

DO NOT use the champion plugs, use the correct NGK ones.
the float is set with the gasket installed, find another book.
the vacum/pressure guage and some T fittings should be less than 20 dollars.
its not a high tech tool.

 

[colayn]

Re: replace all Yamaha carbs Chapter 2

I thought I bought the best manual possible, "Genuine Yamaha" sevice maunal LIT-18616-02-01, $75.
This is disappointing. Now I don't know wheter to trust the manual. Went back and double checked, page 4-18 and it says "without the gasket" and has clear illustration showing no gasket.