THRILLSEEKER

For those of you who have been following my little problem, tonight I blew out all of my fuel lines and changed the fuel water separating filter, then checked the spark plugs, when I pulled the plugs out they all looked fine except for plug # 3, 4, and 5 of which, were loose and the electrodes were completely burned off down to the base of the plug after just 6 hrs. of life after a fresh cam change. How this engine even ran is beyond me. So I replace the bad plugs and head to the lake, engine started fine, and idled fine as soon as I layed into the throttle it started sputtering and backfiring. I shut it of and started it back up and it was making a wierd noise, kind of like the ticking that you hear from a colapsed lifter but not nearly as loud or distinguished, more like a metal rolling on metal sound comming from what seemed to be the carb If I added throttle the noise dissapeared. Then I decide to try to adjust timing, and it doesnt seem to stop the noise or make the engine run any better Now here is the wiered part, I can hear air sucking and blowing through my flame arrestor as the boat surges up and down in the water (engines off), ( exhaust tips underwater), (no flappers). It sounds like I have an intake and exhaust valve both open on one or more cylinders in order for it to make that noise. I am too tired and pissed off to check the plugs at this time of night.

I guess my questions are,

What would cause the plugs to burn up like that?

What can this sound be comming from the carb?

Why so I hear air sucking and blowing through my carb with the surge of the water? and what do all of theese have to do with each other??

Sorry about the book, but I am fed up and have exhausted every possible solution that I can, trying to make this Fu#king motor run right. Looks like I am now going to have to back out of this weekends poker run

GLH

Your right it is long.

wetterthebetter

Sorry to hear the bad misfortune,Hope this may help
Just had the same prob on my boat
#1 burnt plugs are a result of them being loose which caused a lean situation in those cylinders and burnt the tips off the plugs
#2 Because of the lean situation you may have burned valves and or head gaskets i did both in my case no two valves were the same length when checked
#3 The swooshing sound may becoming from a burned valve, when the water hits the back of the and pushes water into the tip ,which then pushes air back through the exh.manifold then to the head then thru the burnt valve then into the intake
Later Stan

Krumbsnatcher

Wow Thrillseeker I am really bummed for you the above explaination sounds good, but I am no expert.

I will check my plugs tommorrow and let you know what I find, we switched carbs and still same problem.

THRILLSEEKER

So do you suggest that I pull the heads off and look at the valves?

28SS

thrillseeker yes pull the heads what was said is correct. Just so you don't feel to bad when i redid my port motor last #1 pug was loose and I burned intake valve. because lost pressure in #1 cylinder the head gasket let loose bettween 1 and 3. be sure to change your oil also,non firing cylinders will leach gas into oil. just hang in there . It happens......

Gary Anderson

You might want to do a compression check first. Also pull the valve covers, check to make sure all the rockers are adjusted, inspect for broken springs, flat cam lobe.
Gary

BROWNIE

"Whooshing" with underwater exhaust is just the air being sucked in and expelled through whatever valves are open. Nothing unusual.

Jersey Tom

Do a leak down test instead of a compression check. It will isolate the problem for you.

JaayTeee

Being the plugs were loose,
they can't transfer heat also.

I repaired a "mere" 4.3 2 years ago,
that the owner forgot to tighten one plug,
it got hot, that cylinder pre ignited, blew a
hole in the piston.

The "ticking" you heard may have been
a compression leak through the spark plug threads.

I would do a comp. test first, then if bad, leak down.

jt