Secondaries not opening up 7.4l carburetor - Solved

So I figured it out...the secondaries were opening up..the backfiring and not going over 3000 rpm was caused by the previous mechanic misplacing the spark plug wires..he had 2 going into 4 and vice-versa...so it was misfiring.
Terrible mechanic.
 
Looks like carb is a weber...I am now leaning towards timing as the issue due to the back fire when started cold...ran great and solid at up to 3000 rpm though, no skips, etc.
Maybe ignition sensor...

So I figured it out...the secondaries were opening up..the backfiring and not going over 3000 rpm was caused by the previous mechanic misplacing the spark plug wires..he had 2 going into 4 and vice-versa...so it was misfiring.
Terrible mechanic.

Moral of the story: Check the easy stuff first.
 
Mercruiser certified mechanic at a large marina charging $150 hour did all the tune up work. I would and should not think I would have to go over everything they did?
Moral of this story is: Find a trusted mechanic or do it yourself.
 
Mercruiser certified mechanic at a large marina charging $150 hour did all the tune up work. I would and should not think I would have to go over everything they did?
Moral of this story is: Find a trusted mechanic or do it yourself.
Even the good ones make mistakes. Mixing plug wires is an easy one to make.
 
If the mechanic had started the motor after he did the work, he would have instantly noticed the back firing and discovered his mistake. Sloppy work is not a mistake.
 
Mercruiser certified mechanic at a large marina charging $150 hour did all the tune up work. I would and should not think I would have to go over everything they did?
Moral of this story is: Find a trusted mechanic or do it yourself.

Sucks, but glad you got it straightened out. Was he working for that marina when he did the work?
 
Yes..crazy part is he was their master mechanic.
I had to take his word for everything as the boat was being transported to me hundreds of miles away. Basically all of the problems the boat had turned out to be his sloppy work.. coolant hoses not clamped, spark plug wires in wrong order (1 was not even plugged in!) Etc.
Luckily it forced me to get up to speed quickly and learn lots..which is always a good thing.
 
Sounds like a carb issue itself. Factory carbs on my 96 330DA were Rochesters. I specifically had them rebuilt (with warranty) and flow tested when I did an overhaul this winter. Oddly enough, port was way too rich even adjusted with the set screws turned all the way in. I warrantied it and now it runs like the day off the show room floor. I did do Electric fuel pump conversions which I recommend and love. Dead cold, I turn ignition switches on, wait 3 seconds (the modules used have 3 second auto-prime) and hold for 2 cycles and it idles flawlessly.
Hello,
Hav the same set up, curious why you switched to electric fuel pumps, were you having any issues ??
 

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