Logo
FULL SITE MENU

Mercruiser 5.7 running on 7 cylinders

J

Jsucci

New member
Hi, I have a 1990 larson san marino with a mercruiser 5.7 in it. Bought it last year in the fall and just got the plugs changed on it this week and the shop said it's running on only 7 cylinders. They said they are not getting and spark from the cap for that cylinder. They tried new wires and nothing. Any thoughts on what it could be? Thank you.
 
I'll have to check it out, it's still at the shop haven't decided if I was gonna have them go thru it or work on it myself
 
Jsucci said:
Hi, I have a 1990 larson san marino with a mercruiser 5.7 in it. Bought it last year in the fall and just got the plugs changed on it this week and the shop said it's running on only 7 cylinders. They said they are not getting and spark from the cap for that cylinder. They tried new wires and nothing. Any thoughts on what it could be? Thank you.
Click to expand...


The ignition coil doesn't know which spark plug wire it is sending spark to.
The sensor unit doesn't know or care either.
The distributor cap does have an important involvement....... has the cap been replaced?
If this is a Merc TB photo-eye triggering system....... the photo-eye wheel may be defective..... has anyone checked this?


If this is truly an issue with NO spark being delivered to #7 cylinder, and yet you have good spark to all other cylinders...... and if this shop cannot figure out why........ I would quickly find a new shop before they end up replacing everything at YOUR expense!



.
 
re: " and if this shop cannot figure out why........ I would quickly find a new shop before they end up replacing everything at YOUR expense! "

I would amend this to say... "If they could not figure it out the first time....I would quickly find a new shop." I would not give this incompetent ( kindest comment) or dishonest shop another shot.


 
Back
Top