Mercruiser 4.3 Backfire and power loss at higher rpm

[Wnafabrication]

Recently have set the base timing by grounding out the purple wire and setting at the recommended 12 deg BTDC. This is the first time I’ve had the boat out since then and also the first time since winter storage. It runs and starts fine until higher rpm (4K plus) where it pops and loses power. My question is, are my issues likely related to incorrect timing?

 

[alldodge]

recommended 12 deg BTDC

It runs and starts fine until higher rpm (4K plus) where it pops and loses power. My question is, are my issues likely related to incorrect timing?

I would say yes, need your serial number, but TBV timing should be at 10 BTDC

 

[Bondo]

My question is, are my issues likely related to incorrect timing?

Ayuh,..... Welcome Aboard,...... My 1st guess is it's goin' lean,.....

Check the fuel filter for anything but clean fresh gasoline,.....

 

[Wnafabrication]

Awesome thanks you guys. I may have mis spoke when I said 12, likely I set it at 10 which is what is on the sticker on the air cleaner but will double check that as well as the fuel filter/separator. If all looks good in the filter, can I go to 8 degrees to try and correct this? I remember a while ago there was a service bulletin regarding dieselling and timing, just not sure what the number was on that bulletin

 

[alldodge]

What is your serial number?