Rectifier caught fire…now what?

[boscoe99]

when did the F motor go up in amperage, maybe I was thinking of larger F motors?

I also thought it strange that the 30 amp fuse did not blow when the RR went up in smoke and fire

If not a direct short and if conditions are right, the failure mode could allow say 20 amps of current flow. Not enough to blow a fuse but enough to melt the R/R. Or a fire to start.

[Gurkenrat]

So my next question is, where do I go from here? Obviously I am ordering a new RR. But so I simply plug it back in and fire thing up? As I mentioned before, I don’t see any other damage or bad wires. Is it safe to assume this drained my battery and is the cause of my issues? I bought the boat last fall and did not realize bad battery connections could fry the RR. It had some pretty sad looking connectors but they held. Knowing what I know now, I replaced them with new, sturdy ones that I will lock washer and nut onto the terminal.

[99yam40]

If not a direct short and if conditions are right, the failure mode could allow say 20 amps of current flow. Not enough to blow a fuse but enough to melt the R/R. Or a fire to start.

but the RR and fuse should handle 30 amps.

I miss read his post and thought he said the fuse did not blow, but it did

[99yam40]

So my next question is, where do I go from here? Obviously I am ordering a new RR. But so I simply plug it back in and fire thing up? As I mentioned before, I don’t see any other damage or bad wires. Is it safe to assume this drained my battery and is the cause of my issues? I bought the boat last fall and did not realize bad battery connections could fry the RR. It had some pretty sad looking connectors but they held. Knowing what I know now, I replaced them with new, sturdy ones that I will lock washer and nut onto the terminal.

If you cannot find another problem try the new RR or take to a shop to chase the problem

[boscoe99]

efecttuvet

but the RR and fuse should handle 30 amps.

A good RR will. A defective RR might not.

The current from the lighting coil could have also caused the RR to smoke and burn.

[99yam40]

A good RR will. A defective RR might not.

The current from the lighting coil could have also caused the RR to smoke and burn.

the motor was not running from what I read

[Gurkenrat]

Key wasn’t even in the ignition.

[Gurkenrat]

What are the odds that if I take it to a shop they just plug new RR in? At this point a defective RR explains most of not all of my problems (started with dead battery then engine died after 30 seconds, fuse blew and smoke under the cap). I guess my concern is that when I get the new RR, is there anything else that could have been defective that could have caused the old RR to cook and could do the same to this one? If so, what are the possibilities and can I test parts out to at least reduce the chances of cooking another RR? And as for the RR, new Yamaha one is quite pricey. I see plenty of them online for a lot cheaper but not sure I like the idea of an online RR considering what I just witnessed. Thoughts?

[boscoe99]

What are the odds that if I take it to a shop they just plug new RR in? At this point a defective RR explains most of not all of my problems (started with dead battery then engine died after 30 seconds, fuse blew and smoke under the cap). I guess my concern is that when I get the new RR, is there anything else that could have been defective that could have caused the old RR to cook and could do the same to this one? If so, what are the possibilities and can I test parts out to at least reduce the chances of cooking another RR? And as for the RR, new Yamaha one is quite pricey. I see plenty of them online for a lot cheaper but not sure I like the idea of an online RR considering what I just witnessed. Thoughts?

The circuit is about as simple as any circuit created by man. Three wires input. Two wires output.And maybe a tachometer frequency signal. If the wires and the battery are in good condition I am not seeing any situation that would render a new component defective.

I have no problem using non OEM parts but that is just me.

https://www.boats.net/product/yamaha...IaAmFbEALw_wcB

https://www.dbelectrical.com/product...230-22144.html

[boscoe99]

The illustrations linked above don't show the tachometer wire that is shown in the sm diagram. Does your damaged RR have the extra wire?

[Gurkenrat]

This is a picture of the wires. All of them are damaged as they leave the RR due to the flame. But the green wire, which has a rubber cap and rubber plug, is the only one burnt on the end.

[Gurkenrat]

This is the back of the CDI. There are burn marks on the crankcase behind it from the RR. No melting but those bumps are suspicious. Any way to test this thing? I really don’t want to spend 1000.00 on a cdi

[boscoe99]

Those bumps are normal.

Seems that you are not using the tachometer wire. I would not hesitate to get an RR from BD Electrical. I have had good luck with their stuff.

[Gurkenrat]

Ok. Thanks. Can’t tell you how much appreciate the knowledge on here.

[99yam40]

This is the back of the CDI. There are burn marks on the crankcase behind it from the RR. No melting but those bumps are suspicious. Any way to test this thing? I really don’t want to spend 1000.00 on a cdi

your service manual should have ohm readings
and some peak voltage reading into and out of the CDI cranking and different RPMs