Logo
FULL SITE MENU

850 mercury 85hp ignition

B

blars33

Guest
"I was on here not long ago bu

"I was on here not long ago but im still running into the same problems. I have a 77 merc outbrard 850. 85 hp. I can start snd shut off the engine numerous times with no trouble. But every so often the engine refuses to start. I dont get spark from any cylinder. The starter cranks fine with plenty of battery juice. But if i hook up jumper cables from my truck and let it run, spark comes back and it starts fine. As I said the battery has plenty of juice and cranks the starter with no trouble. After numerous starts it eventually loses spark again. I also had the battery checked at the local auto parts store and it was fine. Power pack maybe?? I've never seen anything like this. Any help or advise would be greatly appericiated. Thanks"
 
"just guessing here, sounds li

"just guessing here, sounds like your engine has the distributor that needs power and ground supplied to it for spark. You have a bad connection , broken wire or bad key assembly. you need to do some trouble shooting with a volt meter. I have no hands on experience with this engine, but this should help.
http://www.boatpartstore.com/page18.asp"
 
Battery Ign:
There is a red w

Battery Ign:
There is a red wire on the box from the starter solonoid and a white wire from the key. What you are describing may be a voltage drop when the starter engages. Either from too small a battery or that red or white wire is going bad. (Corrosion.)

CD Ign.
Find the Mercury tip switch and remove it. Find the Orange or Black/Yellow wire and remove it fron the box when this happens.
 
I did not think the 77 has a d

I did not think the 77 has a distributor---- If it is a 77 it will have the alternator driven ignition with 4 ignition coils.Which is it?
 
No distributer. It does have

No distributer. It does have the 4 ignition coils.
 
"The only choices left are the

"The only choices left are the black/yellow (orange) stop lead getting grounded or the switch box or stator is failing. It is rare for a sw box to fail that way, but possible. If there is a mercury sw. the remove it. If the moror cranks faster if jumped over, than I wonder if the stator is weak."
 
Back
Top