Plug chop!
Printed From: CorrectCraftFan.com
Category: Repairs and Maintenance
Forum Name: Boat Maintenance
Forum Discription: Discuss maintenance of your Correct Craft
URL: http://www.CorrectCraftFan.com/forum/forum_posts.asp?TID=41550
Printed Date: November-16-2024 at 3:23am
Topic: Plug chop!
Posted By: KooK
Subject: Plug chop!
Date Posted: July-18-2017 at 8:00pm
|
Alright, it's pretty obviously very lean. I'm going to run it up two jet sizes from here. Other than being lean, does anybody see anything else I should be worried about (or do I need better pictures or a better read)? 450cfm Holley (6.5 power valve, 65 main jets)   
|
Replies:
Posted By: KENO
Date Posted: July-20-2017 at 9:28am
|
It seems like you had put in an 8.5 PV last time something was posted. Your stock secondary metering plate has .067 holes for what would be the "main jets" for the secondaries. The plate number is 134-8, you should be going bigger there too. You can get one like a 134-39 that has .073 holes that would definitely add more fuel to the secondaries With the 4160 you either need a new plate like above or a conversion kit to a secondary metering block or a metering plate that you can screw main jets into instead of changing plates. Those look like NGK plugs, what's the number on them? Your engine isn't exactly radical so it doesn't seem like you need to be dumping in massive extra amounts of fuel |
Posted By: TRBenj
Date Posted: July-20-2017 at 9:35am
|
"Pretty obviously very lean".... based on what? What's the soot ring measure vs ideal? I'd ignore the staining on the strap, fuel additive like you said. |
Posted By: KENO
Date Posted: July-20-2017 at 9:44am
|
Here's an adjustable secondary plate that I think would work. Key word is Think https://www.summitracing.com/parts/qft-34-2qft/reviews/?sortReviews=Newest" rel="nofollow - adjustable plate |
Posted By: KENO
Date Posted: July-20-2017 at 9:57am
|
Just my opinion, but I think you're over analyzing all of this You can find at least a half dozen or so different ways of reading plugs and analyzing what they're telling you and they definitely don't all agree with each other 
|
Posted By: GottaSki
Date Posted: July-20-2017 at 11:40am
|
How does it run? Is it dull at a particular throttle setting? Is there a lean surge in any portion of the operating range? For a plug chop to really mean anything, you need to first disable the secondaries and run wot for a spell, then cut the plug. After sorting out the primaries, only then do you move on to the secondaries either those plugs don't have enough run time on them, or , well, if you were that lean to not have a soot ring, there would be drivability symptoms of some type, which we appear to missing that data. ------------- "There is nothing, absolutely nothing, half so much worthwhile as messing around with boats...simply messing." River Rat to Mole |