Ford 302 spark plugs

dubs283

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Run the boat under load at various rpm, 2000, 3500, WOT. Once running under load shut engine off while still in gear at current throttle setting. Inspect a few of the plugs to determine if carburetor jets/settings are rich, lean, or acceptable. Adjust carburetor accordingly. Repeat test at different RPMs until adjustments are acceptable
 

achris

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Run the boat under load at various rpm, 2000, 3500, WOT. Once running under load shut engine off while still in gear at current throttle setting. Inspect a few of the plugs to determine if carburetor jets/settings are rich, lean, or acceptable. Adjust carburetor accordingly. Repeat test at different RPMs until adjustments are acceptable
Or buy a 'ColourTune' spark plug and just watch for the right flame colour..
 

nola mike

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Or buy a 'ColourTune' spark plug and just watch for the right flame colour..
Wow, didn't know this existed. Any experience with it? I was thinking about fitting a wideband O2 sensor to tune, this would certainly be easier. I tried plug chop when I initially tuned my carb. IMO, difficult/impossible to get a reliable reading esp on a boat
 

achris

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Wow, didn't know this existed. Any experience with it? I was thinking about fitting a wideband O2 sensor to tune, this would certainly be easier.
Yes, many years ago. Works well.
 

Lou C

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I got snooping around in there and I found the vaccume port bottom of carb were pcv line runs was really loose. Not only the hose but the brass fitting as well
That could be leaning out the mixture contributing to the problem. Is the carb original to the engine and properly jetted for the application. You said the carb is new is it jetted properly? Keep in mind that plugs run in a range from cooler burning to hotter burning. If everything else is as it should be you might need a cooler plug.
 

Lou C

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Or buy a 'ColourTune' spark plug and just watch for the right flame colour..
I just watched a vid of this thanks for the reference. Going to buy one & try it out on my yard engines then the boat!
Fascinating to watch
 

Jakem

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That could be leaning out the mixture contributing to the problem. Is the carb original to the engine and properly jetted for the application. You said the carb is new is it jetted properly? Keep in mind that plugs run in a range from cooler burning to hotter burning. If everything else is as it should be you might need a

That could be leaning out the mixture contributing to the problem. Is the carb original to the engine and properly jetted for the application. You said the carb is new is it jetted properly? Keep in mind that plugs run in a range from cooler burning to hotter burning. If everything else is as it should be you might need a cooler plug.
 

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Jakem

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Here's what my book shows. It IA also the same as the one that was on it when I bought boat
 

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Lou C

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I would not go by that tag so much but the actual Rochester number on the casting. Those are listed in the page you posted. Not sure where it is on the 2GV but here it is on my Quadrajet 4bbl. Even then you don't know what jets/metering rods it has inside till you look. That's the problem with remanufactured carbs. There are NO new Rochesters, they have not been made (except Edelbrock QJets) in like 30 years.
Q-Jet carb number.jpg
 

Jakem

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Alright....2gv..carb number is 7044185...I took boat out today and it ran excellent...no odd noises or smells...got home and put it on muffs to flush it and about 5 min into it there was a loud bang and everything stopped...I cannot spin it by hand clock wise...counter clock wise till bang...back clock wise until bang...temp ran about 170 ish today...wasn't racing it or anything...oil clean...no water in there..lost
 

achris

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Alright....2gv..carb number is 7044185...I took boat out today and it ran excellent...no odd noises or smells...got home and put it on muffs to flush it and about 5 min into it there was a loud bang and everything stopped...I cannot spin it by hand clock wise...counter clock wise till bang...back clock wise until bang...temp ran about 170 ish today...wasn't racing it or anything...oil clean...no water in there..lost
Gotta start isolating things my man. Pull the drive, see if the engine turns. That tells us where the problem is (engine or drive)...

Chris......
 

Jakem

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So upsetting...alright I will get on it...I appreciate all the help if I could send you all cases of beer I would
 

achris

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Oh, that's not good. Still locking hard. Pull the spark plugs, see if they reveal any secrets. If you have a borescope, stick it in each hole and see if you can see anything nasty. I'd also pull the starter motor and make sure that's not locking things up somehow. If still nothing, pull the valve covers, see if a valves dropped. If that reveals nothing, it's time to think about an engine pull.

Chris.....
 

Jakem

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Like oil pressure was great...no starting issues...no issues what so ever...I could stay on plane at about 3000 rpm and just cruise. No power loss...nothing..
 

achris

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I'm thinking it's more likely top end (head/valve area) than bottom end, so possibly just a head pull.
 
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