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yamaha 8B 8hp, electrical issues?

M

maikel10909

New member
Hello,

I have a problem with my Yamaha, the problem is that after running the engine and stalling it, it sometimes won't start anymore for a few days, to a few weeks sometimes.
why this occurs I don't know but I have this hunch that it has something to do with the electrical components. Maybe water comes at places, that prevents starting the next times until the water evaporated from this place.

How can I test if this is true, and where can such a place occur in an engine, what can I check to prevent this in future times?

Please I hope someone can give me a proper explanation about this, its frustrating because somtime I sail 30km with no issues. Or I sail 1; then stall it and then it won't run anynore for a few days to a few weeks.
 
maikel10909 said:
Hello,

I have a problem with my Yamaha, the problem is that after running the engine and stalling it, it sometimes won't start anymore for a few days, to a few weeks sometimes.
why this occurs I don't know but I have this hunch that it has something to do with the electrical components. Maybe water comes at places, that prevents starting the next times until the water evaporated from this place.

How can I test if this is true, and where can such a place occur in an engine, what can I check to prevent this in future times?

Please I hope someone can give me a proper explanation about this, its frustrating because somtime I sail 30km with no issues. Or I sail 1; then stall it and then it won't run anynore for a few days to a few weeks.
Click to expand...

This is where a $30 manual would help you save a lot of time, money and headache.
 
I have tried the manual, yes. But its not doing anything good. That's why I try to get my answers here, but apparently I can't find them here.
 
This is the 2nd string on this motor....what it boils down to is we dont have enough information about the failure to help you...the first decision you have to make is it a fuel or a fire problem..you say water somewhere in the electrical is suspected...so does the engine have fire at the time of failure?
 
Ah, alright, would be nice if someone said that to me though, but thanks

its a 2 tact engine, which runs fine. Usually, but sometimes if you stop it, it won't do anything for a week or two.
It gets fuel and there is a spark in both bougies, the carburetor is cleaned several times, all the needles and halves has been checked. The fuel goes into the carburetor. But it just won't start.
Even when you spray gasoline directly into the cylinders it won't start until you wait several days to weeks. Amd then it starts and runs just fine. When you stop the engine it has a chance of not starting after that anymore, it happens infrequently and therefore im not so sure where to look for.

I hope this is enough information
 
This is the procedure I go through to check the ignition system for electrical problems: https://youtu.be/MDbvkFM1V_c

I would also run the motor with the cowling off and see if you can spot any water leaks. Water coming from somewhere like the cover over the thermostat will definitely cause you problems.

Stuart
 
Alright, I will certainly try this out thank you..
but can I ask how does a thermostat cause an engine to not start anymore, after it ran smoothly? I assume the thermostat only registers the temperature, and the higher this is. The more cold water is allowed into the engine. I reckon if this became wet,,then it would think the machine is cold and you wouldn't get as much water coolage, but this would overheat an engine, rather then not start an stalled engine. Or am I missing the obvious here, I'll certainly check it, but I was wondering it
 
With regards to the thermostat, it is just if the gasket is bad and it is leaking externally. I have seen this several times spray water up under the flywheel and short the electrics. If you can't see any sign of water coming from the gasket it won't be the problem.

Stuart
 
I have looked into the engine closer, and it seems the contactpoints beneath the flywheel are corroded, which would mean that water indeed comes here. Altough i couldn't find where, i can't acces past the flywheel yet as i can't remove the flywheel yet, since i need special equipment, which i will get this week.
It's unlikely that it's caused by the thermostat gasket or something, because that's in a other place I think (going to double check on that) But I will look for the possible problems.
At least it seems that water comes indeed in the flywheel, so that is a +, I now know what to look for.

Also I have a question: There is a wire, unconnected(you can see it hanging out beneath)
Why is that there? does anyone know what's it for
tumblr_nr4nxnny481s962mwo1_540.jpg
 
Those two wires are likely to be from a lighting coil. These supply an AC current that can be connected to a regulator/ rectifier to charge a battery.

Stuart
 
The flywheel finally came off after a while work. The contacts are rusted and the condensators didn't looked to good, tomorrow we gonna take the bottom part off and check the membranes there.

So the problem is likely to be this, but now we gotta find the problem.
 
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