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454 msd cured problems

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tankmfd

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"was having backfires and surg

"was having backfires and surging everyone said fuel or carb problems went to msd setup and all is good. just got a couple questions, what plugs should i run for best results/heard they eat up plugs and should i change the timing curve installed it as it came, and what wot should i be hitting am hitting 3500-3600 right know with 17 x 19 was thinking of going to a 17 x 17 i cruise it at 2950-3100 rpm dont want to wear this engine out... 25 seavee 88 with 200 gal of fuel and gear am estimating weight on normal trip at 7000 ish pounds"
 
and at cruise burn 13.5 to 15.

and at cruise burn 13.5 to 15.5/16 gallons thimk im running over propped and thats making her thirsty...
 
"I assume those are small bloc

"I assume those are small blocks. (If not, something is major league wrong here!)

Before you do anything find out (with a timing light) what the max advance is. Rev her up good and see. (You'll need to mark the damper pulley at that point, or use an advancing timing light.) With all those changes you might not be getting full advance, or too much.

The rate of spark advance isn't important in marine engines, just where it's all in (which should be around 3,000 -3,500 rpms).

Finally, you will see MORE gas burned if you drop back to 17 x 17 props, and engine wear will increase with the higher revs you'll need to run.

Jeff"
 
""was having backfires and

""was having backfires and surging everyone said fuel or carb problems went to msd setup and all is good"
hmmm, that's pretty suspicious. Anyway, high energy systems want ~ .045 gap on the plugs. Your WOT is low, but what engine? Are you sure all cylinders are firing? Follow Jeff's advice on measuring the max advance as well."
 
"I don't come close to the

"I don't come close to the knowledge of Dave or Jeff so I suggest you try their suggestions first. The photo of me is one of me scratching my head trying to determine what is wrong with my boat. I have had a couple of 1984 454 CIDs for 22 years. When I get firing out the exaust pipes the first thing I do is check my spark plugs. Over the years mine have had the tendency to foul. When they do one of the symptoms is firing at the exhaust pipe.

With regard to surging, I run fairly small fuel pumps that only support 2800 RPM under load. If I get anywhere close to max capacity of the pumps the engines will surge. Therefore I would suggest you look at fuel supply, filters, pumps strainers etc. Other threads suggest measurement of presssure at the carb. I have a pressure gage just before the carb. Warning - don't run your engines starved for fuel. It will result in major repair bills.

Other things you might check is the condition of your spark wires and coil wire. These can result in cross firing if they are wet or cracked, which could be manifested in firing at the exhaust pipe or back through the carb.

You mentioned back fire. If you mean firing back through the carb, I have experience with this one also. If you keep your engines for 22 years you have time to experience a wide varity of problems. Mine turned out to be very dirty carbs caused by a load of very bad gasoline in 2003. I had them rebuilt and the problem was resolved.

I would suggest you try some of these things and give us some feedback and someone would be happy to work with you further. This is a very helpful forum.

I am writing from Geneva Switzerland although I live near Memphis, TN. It is not quite boating weather here yet."
 
"Chuck,

I don;t know how yo

"Chuck,

I don;t know how you do all that flying. To get from NJ to Disney World...I gotta drive."
 
"Chuck; I did a boat ride on

"Chuck; I did a boat ride on Lake Lucern one time. Huge Swiss flag on the stern, mostly darkened by diesel soot. I also saw the only boats I've ever seen near there that had wheels permanently mounted to the bottom of the hull, to aid in moving around dry land. Wild..
Great country, though."
 
I wish I could say I was here

I wish I could say I was here as a tourist on vacation. As it turns out I am working about 15 hours each day. I think I am getting too old to keep it up. I am ready to go back to the boat because it is getting warm on the Tennessee River.

Sorry for the "off topic". I'll stop now.

Chuck
 
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