55HP 2 stroke Yamaha Not Firing

[ChuckB1954]

Was able to sort thing out. Needs some fine tuning.

[99yam40]

congratulations the beast is alive.

well things are looking up for you.

did you take any peak voltage readings and write them down for later trouble shooting this motor by you or someone else in the future?
did you find the specs on the gap you were looking for?
seems like the manual should have had them.

practice doing all of this is a good learning experience on troubleshooting

[ChuckB1954]

congratulations the beast is alive.

well things are looking up for you.

did you take any peak voltage readings and write them down for later trouble shooting this motor by you or someone else in the future?
did you find the specs on the gap you were looking for?
seems like the manual should have had them.

practice doing all of this is a good learning experience on troubleshooting

Thanks! What voltages are you referring to?

As far as the gap, I assume you are referring to the pulser coils(?) I could not find any info on them, so I put them back in the way they came out. I saw no way to change the gap. The slot allowed them to be slightly rotated.

[99yam40]

Thanks! What voltages are you referring to?

As far as the gap, I assume you are referring to the pulser coils(?) I could not find any info on them, so I put them back in the way they came out. I saw no way to change the gap. The slot allowed them to be slightly rotated.

peak voltages to and from the CDI.
best way to troubleshoot a CDI ignition system.

sorry, I thought you were asking about a gap on the pulser coil

[ChuckB1954]

peak voltages to and from the CDI.
best way to troubleshoot a CDI ignition system.

sorry, I thought you were asking about a gap on the pulser coil

Oh, I got you.. Yes, seems like it would be quick and very useful when a running engine is having problems. Not to mention a lot easier than disconnecting the CDI leads and measuring the resistances, which probably would be the next step if the voltages previously measured have changed.

[ChuckB1954]

Another problem I have to deal with.. The throttle cable end is too short. It is only holding by 3 threads! I'm sure they sell a longer end, but you almost have to have a part number. Anyone?


(the tie wire on the shift cable was done by the previous mechanic, I plan to correct it)

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[TownsendsFJR1300]

I gather you have all the play out of the throttle cable and it just slips over the pin (W/O) pulling or pushing?

Great work BTW, been following the thread!

[99yam40]

did you follow the link and sync procedures before finding out the cable was too short?
need to make sure everything is where it should be.
never heard of finding a cable just a little longer before, but that is just me.

[ChuckB1954]

did you follow the link and sync procedures before finding out the cable was too short?
need to make sure everything is where it should be.
never heard of finding a cable just a little longer before, but that is just me.

The cable is fine, it's the bolt on eyelet that was too short. I found a longer one, so problem solved.

[ChuckB1954]

Trying to figure out the timing now.. The book is not real clear, but from what I understand, the pick up point is where the timing linkage makes contact with the roller on the carb throttle linkage allowing more fuel. The idle timing is just that.. checked when the engine is at idle.

So using my timing light and the engine being at idle, timing should be at 5 degrees after TDC, When the throttle is applied, only the timing plate should move, until 4 degrees before TDC is reached. With the throttle applied after 4 degrees before TDC, both the timing plate and the carb linkage should move. Is this correct ?

[99yam40]

I have not read your manual , so cannot comment on that wording.

I know that as timing advances the RPM goes up(even without moving the throttle plates), and probably needs to be advancing as the throttle plates open i so I think you are correct

[ChuckB1954]

Took it out today to test it. I never tried putting it in gear at home on the hose. It idles decently, but when I put it in gear the engine starts to die and when I try to over come this by giving it throttle, the engine dies completely. One thing I'm not sure of.. when I go from idling in neutral and push it in gear, none of the linkage move.. not the timing advance and in turn nor does the throttle linkage. Is this normal? I would think that the timing should advance enough to give the engine more RPM's so it wouldn't bog down.

[99yam40]

as far as I know, motor should go into gear without moving throttle.

I am fairly sure the final carb adjustment should be with motor in the water after motor has warmed up.
the back pressure on the exhaust can change it some

have you ever played with chainsaws or weed-eaters.
if not rich enough at idle they do not transition well to higher RPM

[ChuckB1954]

as far as I know, motor should go into gear without moving throttle.

I am fairly sure the final carb adjustment should be with motor in the water after motor has warmed up.
the back pressure on the exhaust can change it some

have you ever played with chainsaws or weed-eaters.
if not rich enough at idle they do not transition well to higher RPM

Thank you. That makes a lot of sense.. I have checked and rechecked the accelerator and control linkage lengths (default/ballpark dimensions @ 138MM and 50MM per the manual) and also the idling and pick up point timing and it is pretty much spot on. I need to leave this area alone and move on to the fuel mixture situation.

Initially the carb float bowls were full of shellac. I cleaned them out and blew out all the jets and openings with brake cleaner with compressed air, using a whole can, but as you mentioned, the problem points to correct fuel mixture. It is very probable that they still have problems. I replaced the carb gaskets, but not the reed valve gaskets. I will also test for a vacuum leak. I set the carb pilot screw to default, which is two turns out.

[99yam40]

may need to use a heated sonic cleaner to make sure all passages are clean

that gunk can be hard to get out of everywhere