Year model of 850/ plus a few questions

way2fast72

Cadet
Joined
Mar 9, 2007
Messages
16
serial# 4595143. was given to me by previous owner.He claims it got hot and quit him on the lake.I have the controller,so I put it on a stand and connected a battery.pulled all the plugs and compression is 140 psi for every cylinder plus or minus 5 psi.I think the motor is probably ok,except when I went to test spark I have none on any cylinder.Any suggestions on where to start troubleshooting ignition system?
 

tashasdaddy

Honorary Moderator Emeritus
Joined
Nov 11, 2005
Messages
51,019
Re: Year model of 850/ plus a few questions

your compression is great, i'm leaving the electronics to the merc experts. there are a lot of guys here more qualified on mercs, than i.
 

ricksrster

Commander
Joined
Jun 19, 2005
Messages
2,022
Re: Year model of 850/ plus a few questions

Do you have a DVA? If not, you can start here with testing the Resistance of the Stator, Trigger, and coils. 1977 850.
Stator: Disconnect the blue and blue/white wires at the switch box. Ohms reading should be between 5800 - 7000.Do the same with the red and red/white wires. Reading should be between 2200 -2400 Ohms. DVA voltages should be 180v+ for the blues and 20v+ for the reds.
Trigger: Brown to white/black and Purple to white should bothj have 800 - 1400 Ohms Dva 4v+.
Coils: .02-1.0 ( somewhere less than 1 Ohm ) for the primary and 800 - 1100 Ohms for the secondary.
 

Chris1956

Supreme Mariner
Joined
Mar 25, 2004
Messages
28,080
Re: Year model of 850/ plus a few questions

Way, I could not find you motor via the serial munber. Is it 4 cylinder? Is it Distributor Ignition?
 

ricksrster

Commander
Joined
Jun 19, 2005
Messages
2,022
Re: Year model of 850/ plus a few questions

He has a 1977 850. No distributor.
 
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