Timing

[sasko1980]

Yamaha '95 70HP 2-stroke

Can anyone (in details) explain how to set timing procedure from TDC to WOT without using a test prop for WOT.
Assume that boat is out of the water-trailer!
Thx

[sasko1980]

I was looking for a procedure that can be used for many (most) yamaha motors that are similar, not just yamaha 70. In that way, all forum members could find their answers to timing questions, and potentially solve timing problems

Ignition timing adjustment parameters for full retard and full-advance and RPM that belongs to this two points can be found in service manuals along with throthle sensor control lenghts and all other param...

Maybe the full retard setup isnt so complicated ,but the full advance on WOT due to motor rev close to 5500-6000 RPM is.
How can it be done without test prop, is there a way to set it without one.
Is there a trick to get around!!!
I think that fixing/strap/rope a boat to a something and to rev it up with a normal prop is not a option, too dangerous.

Procedure for timing should be as sticky thread.
As cleaning the carbs should be aslo as a sticky thread because 50 % of forum questions and answers are cleaning the carbs and fuel systems.


Thx

P.S. This forum is called parts forum & how to's. Parts yes, how to's - not so

[TownsendsFJR1300]

I posted elsewhere (and may be wrong), but why not simply disconnect the carb linkage. (Carbs do NOT open)

Start the engine, (with the timing light attached) (carbs at idle) and advance the timing fully. Check and adjust.

Yes, the idle will rise some with the advance but not much and you can adjust the WOT advance..

Depending on the set up, it should work...


.


I don't know of a sticky for carb cleaning but it has been addressed MANY times.

Yamaha has made various configurations of carburetors, with prime start, accelerator pumps, choke butterfly, etc.

As posted many times, remove the bowl, float ALL JETS, ANYTHING where water / corrosion can hide and clean spotless. Simply spraying carb cleaner at a carb don't cut it. If you can't see light thru the jet, it isn't clean...

Varnish is the biggest issue as is clogged jets thanks to old, crappy, un-treated, Ethanol fuel...

[sasko1980]

I posted elsewhere (and may be wrong), but why not simply disconnect the carb linkage. (Carbs do NOT open)

Start the engine, (with the timing light attached) (carbs at idle) and advance the timing fully. Check and adjust.

Yes, the idle will rise some with the advance but not much and you can adjust the WOT advance..

Depending on the set up, it should work...

Didn't noticed that post, but a good plain answer is sometimes the best.

Thx, I'm OK with that
P.S. just wanted a detailed timing procedure for others to be helpfull, how to attach a timing light, how to measure, what to look for (TDC), where etc..

[donsmarine]

this is a great service time saver, lots safer too!!

[boscoe99]

I was looking for a procedure that can be used for many (most) yamaha motors that are similar, not just yamaha 70. In that way, all forum members could find their answers to timing questions, and potentially solve timing problems

Ignition timing adjustment parameters for full retard and full-advance and RPM that belongs to this two points can be found in service manuals along with throthle sensor control lenghts and all other param...

Maybe the full retard setup isnt so complicated ,but the full advance on WOT due to motor rev close to 5500-6000 RPM is.
How can it be done without test prop, is there a way to set it without one.
Is there a trick to get around!!!
I think that fixing/strap/rope a boat to a something and to rev it up with a normal prop is not a option, too dangerous.

Procedure for timing should be as sticky thread.
As cleaning the carbs should be aslo as a sticky thread because 50 % of forum questions and answers are cleaning the carbs and fuel systems.


Thx

P.S. This forum is called parts forum & how to's. Parts yes, how to's - not so

How to's are provided but they are in the form of words (and maybe an illustration or too) that are tailored for a specific posters problem. As best as he understands the problem and as best as we can understand the problem given what we are told.

As noted, there are so many different Yamaha motor configurations, which can have so many different problems, that it is impossible to provide tutorials for every model, for every problem, for every body.

And think about this. There are many many Yam users with various (good or bad) skill levels. Some can tear a motor completely down and reassemble it just from memory. Then there are those that don't know what a screw driver is or which end of the screw driver does what. We here have no idea who we are talking to or what their skill level is. Or, their level of comprehension. We try to help those that are not here in the US and who are trying to tell us their problem in a language (English) that is not native to them. It is a tough job trouble shooting a problem. All the moreso via a computer screen.

[donsmarine]

Boscoe, is this a good or bad idea, I don't understand what you are trying to say for the people who have bad skill levels. Enlighten please.

[99yam40]

I feel he was saying we do not normally provide step by step with pic to do things.
if people understand what to do from what we post and can do it from the instructions given then good for them

[TownsendsFJR1300]

Sounds like Donsmarine is asking for a second opinion on my suggestion on the timing issue.

Which is the same question the original OP asked for.


So far, no one has whipped on me (yourself included-in either thread), but I'd like to know as well.

If there's separate linkage for advancing the timing, common sense, at least to me, it should work...

I'd rather hear Rodbolts opinion as well, he's a hands on, master tech.

Of course this would be a "backyardian" method for non professional NOT working out of a Yamaha shop with Yamaha specific tools...

[99yam40]

I am no expert, but
I used that method on my C40.
made sure where the wiper went to when at WOT, marked that, disconnected the linkage, started motor, check idle timing and then moved the wiper to where I marked it for WOT and checked with timing light.
Did not run it long, just enough to get a reading.
I was having a problem with the timing at idle being off even when the wiper was at the factory mark.
timing at the factory WOT mark was close enough.

Did the final check on the water under a load. just need an extra person to drive the boat

Sounded like the OP was looking for a more detailed step by step procedure including pic showing how and where to hook up light ,where to get the reading, how to find TDC , etc.etc.
The whole ball of wax

[TownsendsFJR1300]

Thanks for the confirmation, at least on your engine, that the procedure (checking timing without a wheel) can work...

[rodbolt17]

do what you wish but at the end of the day WOT timing needs to be checked at the correct RPM and LOAD.
either hang off the back or buy/beg/borrow the test wheel.