F50tlrc blowing starter relay

[CaptnMullet]

My 2004 F50TLRC is very hard to start due to what appears to be fuel problem. I have had 2 starter relays go bad trying to get the motor to run. Anyone else had this problem and if so, any advice?

Come to find out my 2nd starter relay didn't go out and I am back trying to solve the fuel problem. I have to "pump" the idle arm up and down on the controls to get the engine to fire. It will run for a couple of seconds and then die. Prime start problem? Fuel pump problem? Both??
I changed the fuel lines, am using new fuel. Even tried the fuel tank and lines from my little jon boat and it acts the same.

[rodbolt17]

fix both problems.
one is the fuel system the other is bad connections to the relay causing excessive current draw.

[boscoe99]

A good connection has the lowest amount of electrical resistance.

A poor connection generally will have higher electrical resistance.

As the resistance increases current flow decreases.

How does a bad connection to a relay result in excessive current draw?

[99yam40]

higher resistance causes lower voltage to the starter motor,
lower voltage causes more amps to be drawn to do the same amount of work(turn the motor)

[boscoe99]

According to Ohms law it does not add up.

E = Voltage
I = Current
R = Resistance

For current the formula it is I = E over R

If E goes down (lower voltage) while the resistance stays the same, then I goes down. Not up.

But, this is for a fixed resistance. Perhaps a motor is drawing a different amount of current even though the voltage is lowered, because it is trying to create power. To get the same power with a lesser voltage then the current would have to increase.

Now in the case of a relay, what needs to be known is how it is failing. Is it in the control side or in the power side. The control side does have a fixed resistance so its connections (poor or good) should be subject to Ohms law. More resistance means less current.

The power side is where the majority of the current flow is. Some, to be more specific, should it be said that the electrical connections on the power side of the relay, and all other connections that are in the power circuit from the battery to the starter motor need to be checked for cleanliness and tightness?

I need to go and study this some more.

But I do agree that a hard to start issue needs to be fixed first. Otherwise, there will be abnormal wear and tear on the starter motor side.

[99yam40]

Yes a motor is different from a (say)heater element.
Lower voltage on a heat element will just produce less heat.
A motor will draw more current with less voltage because it wants to produce the HP it was designed to out put so I needs more amps.
This is true for DC or AC motors.
This is also why they say not to run long runs or wiring without increasing the size(gauge) of the wire.

My bet is the internal contacts in the relay are burning up, they are not that robust from what I have read on the Yamaha start and trim relays. Saving the cost of copper in them

[boscoe99]

Yes a motor is different from a (say)heater element.
Lower voltage on a heat element will just produce less heat.
A motor will draw more current with less voltage because it wants to produce the HP it was designed to out put so I needs more amps.
This is true for DC or AC motors.
This is also why they say not to run long runs or wiring without increasing the size(gauge) of the wire.

My bet is the internal contacts in the relay are burning up, they are not that robust from what I have read on the Yamaha start and trim relays. Saving the cost of copper in them

More to think about. Shown below is a typical Yamaha starter circuit. From the key switch, current flows through first the starter relay to ground. Current then flows across the relay power contacts and then on to and through the starter solenoid to ground, but only through the solenoid coils. None of this current flows through the starter motor itself. Since relay/solenoid coils are purely resistive devices, then a poor connection would result in less current flow, not more current flow. Wouldn't it?

Now granted, a poor connection at the starter motor solenoid power terminals could result in a greater current flow through that device as it flows to the starter motor itself, but that would affect only the starter and/or the starter motor solenoid. Correct?

The OP is reporting that the starter relay is failing. I don't see this device drawing any more than normal current no matter what the condition of the connectors may be. Am I missing something?

[rodbolt17]

whats the difference between a heating element, say in your dryer, and a straight piece of wire?
as far as the electrons see it they both look like this.

element ______________________
wire _________________________

a DC motor or most any DC circuit wants MORE electron flow, add a resistance and you add heat.

so maybe an excess current draw wasn't a great choice of words but its kinda what happens.
not a current flow because it did not increase the amperage nor the wattage but you drastically can increase the heat.

now we are going to add the fact that the start circuit, per that diagram, is a series parralell circuit and we can bring on two laws, one is kirchoffs law of voltage the other, kirchoffs law of current.
think of it, just before that starter motor, that electrically looks like a dead short, engages we have full voltage to the relay from the battery, now the stater engages and is an electron hog yet we still have to keep the relay engaged.
aint but so many trons can get out of the battery per second.
yet it has to feed the starter,relays,ign and in the case of an EFI the pump and injectors.

so yes you have two issues.
that 04 model 50 should start in less than 20 seconds in any weather.
I have a commercial used 04 50 that probably has over 7000 hours now and still has all the original electronics including the starter .

[FabricGATOR]

My 2004 F50TLRC is very hard to start due to what appears to be fuel problem. I have had 2 starter relays go bad trying to get the motor to run. Anyone else had this problem and if so, any advice?

My advice is don't keep cranking the crap out of the starter system when your motor doesn't fire.

Like my girlfriends, they crank the engine in the parking lot until the battery is dead, then they go find someone with a set of jumper cables...

You need to take it easy on your equipment. I don't know what the actual duty cycle is, but I'd imagine cranking for about thirty to forty seconds maximum and then let it cool for about five minutes. If your cranking and pumping your throttle for two minutes your gonna find the weakest link.

Trouble shoot the start issue.

$0.02 please... what happened to the cents key?

[boscoe99]

My advice is don't keep cranking the crap out of the starter system when your motor doesn't fire.

Trouble shoot the start issue.

I think you are correct. This appears to he a hard start issue that is wearing out relays.

Manual says to not crank a motor for more than five seconds. Stop and let the starter motor and other stuff cool down. Then try again for not more than five seconds.

Folks that have a hard start issue may see other expensive parts wear out sooner than they should. Relays, solenoids and expensive starter motors.

Another fellow was wanting to add an electric starter to his hard to start manual pull four stroke. I asked why and his answer was "it is hard to start".

[99yam40]

More to think about. Shown below is a typical Yamaha starter circuit. From the key switch, current flows through first the starter relay to ground. Current then flows across the relay power contacts and then on to and through the starter solenoid to ground, but only through the solenoid coils. None of this current flows through the starter motor itself. Since relay/solenoid coils are purely resistive devices, then a poor connection would result in less current flow, not more current flow. Wouldn't it?

Now granted, a poor connection at the starter motor solenoid power terminals could result in a greater current flow through that device as it flows to the starter motor itself, but that would affect only the starter and/or the starter motor solenoid. Correct?

The OP is reporting that the starter relay is failing. I don't see this device drawing any more than normal current no matter what the condition of the connectors may be. Am I missing something?

I was not aware the F50 had a starter relay and a starter motor solenoid.
Definitely set up different than my old C40 2 stroke.
I was thinking he was referring to the solenoid that feeds main power to starter when he said starter relay

[boscoe99]

Well, you may be right about an F50 not having both a starter relay and a starter solenoid. I just found and used the wiring diagram that was most convenient. The one shown is for an F150.

Now, I have more work to do.

[boscoe99]

I'm back. The F50TLRC uses both a starter motor relay and a starter motor solenoid. Appears to be the same general configuration as is used for the F150.

[rodbolt17]

most all the F motors above 50 Hp use a relay AND a start solenoid.
most older sterndrives are wired this way as well.
in the stern drive world we referred to them as slave and master solinoids.
wanna guess why they did it this way ?

[boscoe99]

most all the F motors above 50 Hp use a relay AND a start solenoid.
most older sterndrives are wired this way as well.
in the stern drive world we referred to them as slave and master solinoids.
wanna guess why they did it this way ?

I'll bite. Why?

My first thought is to use more parts. If three parts are needed to get a job done then Yamaha is going to use five, or more.