Mercury model 800 charging problem and trim/tilt

[Retired old guy]

We have an old Mercury model 800 80 hp motor on a 28 foot pontoon boat. It has always been great and dependable until this year. I have two problems:<br /><br />1. It has a new battery and after being on a charger in the garage over night, it is put on the pontoon. The motor starts easily. After being run for a considerable time with the lights on and radio running, the battery seems to loose its charge to the point where the motor will barely turn over to start, if necessary. Does this motor have an altenator? Could the diodes be bad?<br /><br />2. After much work we got the tilt/trim to work, but it appears that the limit-switch only allows the motor to tilt up about 60%. By holding in the plunger on the switch we can get the motor up all the way. When inspecting the switch and the tang on the motor, it appears that it should limit how far down the motor goes, not up?

 

[Clams Canino]

Re: Mercury model 800 charging problem and trim/tilt

1. The charging system has two parts a stator (alternator) and a rectifier. Odds are the rectifier is toasted. Ohm it out as per the manual, it has 4 diodes to test both ways.<br /><br />2. Bypass that limit switch. It is desgned to limit "up" on the old 3 button trim controll.<br /><br />-W

 

[Retired old guy]

Re: Mercury model 800 charging problem and trim/tilt

Originally posted by Retired old guy:<br /> We have an old Mercury model 800 80 hp motor on a 28 foot pontoon boat. It has always been great and dependable until this year. I have two problems:<br /><br />1. It has a new battery and after being on a charger in the garage over night, it is put on the pontoon. The motor starts easily. After being run for a considerable time with the lights on and radio running, the battery seems to loose its charge to the point where the motor will barely turn over to start, if necessary. Does this motor have an altenator? Could the diodes be bad?<br /><br />2. After much work we got the tilt/trim to work, but it appears that the limit-switch only allows the motor to tilt up about 60%. By holding in the plunger on the switch we can get the motor up all the way. When inspecting the switch and the tang on the motor, it appears that it should limit how far down the motor goes, not up?

 

[Laddies]

Re: Mercury model 800 charging problem and trim/tilt

Old guy it's like clams said the trim switch should stop the up travel on the trim just before the swivel bracket comes out of the side brackets, actully it should stay inside them about a inch to support the motor in a turn. it can be adjusted with the s/steel strap that touchs the push button switch---Bob

 

[Retired old guy]

Re: Mercury model 800 charging problem and trim/tilt

Thanks very much!

 

[Retired old guy]

Re: Mercury model 800 charging problem and trim/tilt

Do you think it's best to just replace all 4 diodes? Any idea how much they cost and where to get them?

 

[emckelvy]

Re: Mercury model 800 charging problem and trim/tilt

You have to replace the entire assy as a unit: this is the latest version of the rectifier assy that can be used to replace yours, even if yours doesn't physically look the same:<br /><br /> http://www.boatfix.com/bykeywordnew2.asp?textfield=154-6770&texttype=2&submit=Search

 

[achris]

Re: Mercury model 800 charging problem and trim/tilt

$24.80!!! Those things are over $100 in OZ.

 

[Retired old guy]

Re: Mercury model 800 charging problem and trim/tilt

Thanks very much! Sure hated to see this ol' 800 just be thrown out as junk.