Logo

2008 60 hp EFI (not big foot) slight miss at idle then will not go to full throttle

mmrando

New member
2008 Mer 60hp EFI has a slight miss at idle then will not go to full throttle, runs rough. This is my first experience with an outboard and want to get this right. I am guessing maybe a fuel pump issue or bad plugs. We have replaced fuel lines and cleaned plugs, will replace fuel filters when they come in. Have checked for tightness of the anchor bolts on the fuel pump.
 
has a slight miss at idle then will not go to full throttle, runs rough.
Sounds like either a lack of spark or fuel issue. Verify each spark plug can jump a 7/16" gap w/a loud snapping blue spark...use a spark test board available at most autoparts stores.
...cleaned plugs
Try new plugs.
 
So here is what we have done thus far with no change in performance. Treated fuel, changed fuel lines, new lower fuel pump, changed both fuel filters and all new plugs. Really don't want to have to take to the shop for repairs. Hubby is pretty handy on motors but doesn't have exp. with the EFI motors so he is a bit reluctant to dive too deep into this thing. Is there anything else we might be able to do? We took it out Sunday, still slight miss, ran rough up to about 4000 rpm, smoothed out but then wouldn't go above the 4000rpm mark. Never dies and always starts right off.
Thanks

Sounds like either a lack of spark or fuel issue. Verify each spark plug can jump a 7/16" gap w/a loud snapping blue spark...use a spark test board available at most autoparts stores. Try new plugs.
 
Last edited:
Do you remember what the old plugs looked like before cleaning them...what color were they? Get a cheap spark tester at an autoparts store and test the spark at the end of each plug wire. Get one that the gap can be adjusted. Open the gap to 7/16" and see if there is a loud snapping blue spark at each wire end.
 
Do you remember what the old plugs looked like before cleaning them...what color were they? Get a cheap spark tester at an autoparts store and test the spark at the end of each plug wire. Get one that the gap can be adjusted. Open the gap to 7/16" and see if there is a loud snapping blue spark at each wire end.


They were sutty looking. Since my last post, I have learned that this motor is still under wàrrnty. When the original owner purchased in 2009. MERCURY had a ptomotional earrenty program so it has a 5 yr warrenty, good until March. 2014. Now just got to pray ehatever is wrong will be covered.
 
They were sutty looking. Since my last post, I have learned that this motor is still under wàrrnty. When the original owner purchased in 2009. MERCURY had a ptomotional earrenty program so it has a 5 yr warrenty, good until March. 2014. Now just got to pray ehatever is wrong will be covered.

07/08/2013 UPDATE: Just wanted to thank everyone for their input. However, after discovering Wednesday that we still had warrenty left on the motor, thank GOD!, I took her into a Mercury dealer. Bad coil at number 5 cylinder and with the recall that had been previously issued by Mercury, even though my serial number was not tagged as being in that recall, Mercury gave the go-ahead to replace all the coils. Shop said she looks and runs like new again. Can't wait to get her back out on the lake.
 
Back
Top