150 mercury xr6 prop size

[dhenson61]

Have a 2002 Mercury 150 xr 6 that is on a 186 Triton. The trigger according to the mechanic has gone out and has to be replaced. He says that it may have gone bad due to the wrong size prop on the boat which allowed the motor to turn to many RPM's. Has anyone ever heard of this and what size pitch would be appropriate for this engine size?

 

[Dukedog]

Re: 150 mercury xr6 prop size

What kinda rpm are ya turnin'? Never had a problem like that on switch box motor but yours is a CDM motor and should have a rev limiter on it. Just doesn't seem ta add up. Maybe someone that knows tha newer electrics better than me will jump in on this one..............

 

[achris]

Re: 150 mercury xr6 prop size

Can't happen... The trigger is just a coil of wire that a magnet flies past. That generates a voltage spike in the coil, which is read by the switchbox (or CDM) as a requirement to produce a spark on that particular cylinder. The trigger will continue to produce voltage spikes in excess of 100,000 revs without a problem... Whether your engine stays together at that speed is another thing.

The correct size prop for your boat is the one that allows the engine to reach between 5000 and 5500 rpm at wide open throttle, with a normal load on the boat...

What can kill a trigger? Age (unlikely as it's only 8 years old). If the windings have been subject to moisture, that would allow the copper wire in the winding to corrode. I guess the only way to tell would be to do an autopsy on the old trigger once it's out.

Chris........

 

[j_martin]

Re: 150 mercury xr6 prop size

What can kill a trigger? Age (unlikely as it's only 8 years old). If the windings have been subject to moisture, that would allow the copper wire in the winding to corrode. I guess the only way to tell would be to do an autopsy on the old trigger once it's out.

Chris........

I think a faulty input circuit in the electronics can take out a trigger also. Best to check those voltages after the new trigger is installed.

I agree with achris. You select prop size to keep the engine within it's peak operating range. If your load varies widely, as in a ski boat, you can bump the limiter a little without harm. I use different props on different days, depending on the duty, racing (fishing) or playing (camping or skiing).

If you don't have a tach, get one. It's invaluable, and will pay for itself many times over giving early warning for many engine or setup faults.

hope it helps
John



hope it helps
John

 

[Faztbullet]

Re: 150 mercury xr6 prop size

Like everyone else has posted...no can do.. I would ask him to double check trigger ohm and DVA readings before replacing. A couple of bad CDM modules or bad ground on mounting plate will cause a no spark symptom, the CDM modules can be checked on the engine or the bench with a ohm meter.