clear (dry or glazed) plug fouling??? Stumped....
06-09-2016, 09:59 PM
#51
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On same theme.
How are you slowing down ? Suddenly ?
Maybe somehow, internally or externally, you are getting a drink of water when slowing down.
How are you slowing down ? Suddenly ?
Maybe somehow, internally or externally, you are getting a drink of water when slowing down.
Originally Posted by Bill 3
Twin 515 cu. in. NA right at 600hp. 850 Holleys with Dart intake, iron heads. MSD distributor with 6M MSD boxes. My issue is with fouling plugs, and they come out looking clean. Plugs are NGK R5674-7. They do not gradually foul at idle, but no idle is the result after a run.
I run 5 - 10 miles down the lake, 3500-4000 rpm come to a stop and both engines die. Very hard to restart, cough, spudder and barely run given some throttle. No way to put it in gear with out dying. Check over everything and all seems right. Carbs not flooding or dripping. Floats are set properly. Put in new plugs and all is well again.
I run 5 - 10 miles down the lake, 3500-4000 rpm come to a stop and both engines die. Very hard to restart, cough, spudder and barely run given some throttle. No way to put it in gear with out dying. Check over everything and all seems right. Carbs not flooding or dripping. Floats are set properly. Put in new plugs and all is well again.
Last edited by SB; 06-09-2016 at 10:01 PM.
06-10-2016, 04:41 AM
#52
Platinum Member
Platinum MemberThread Starter
Originally Posted by mike tkach
with the extra length of the muffler,s are the tips under water- when ideling or stopping after on plane?
Originally Posted by SB
On same theme.
How are you slowing down ? Suddenly ?
Maybe somehow, internally or externally, you are getting a drink of water when slowing down.
How are you slowing down ? Suddenly ?
Maybe somehow, internally or externally, you are getting a drink of water when slowing down.
I do have a whole rant about Gibson. I purchased used mufflers on OSO. Get them and find out they are 4.5" in and only 4" out. Contact gibson and they tell me someone had modified them, they should be same in and out, but also there R&D guys say there should be no restriction in flow (makes sense - not to me anyway). So I ordered a new set, they show up, same thing, 4.5" in and 4" out. I contact them, since there must be some kind of mistake --- I get no response. I guess that is the way businesses are run these days.
So I have been running the mufflers regardless. With all this said though... Do you guys think the turbulence from the muffler and the restriction in going from 4.5 to 4" could be causing an issue that doesn't show up at idle?
06-11-2016, 08:08 AM
#54
Platinum Member
Platinum MemberThread Starter
Fellas, I am an IDIOT! I made an assumption that everything was new regarding my ignition - well, most of parts on these engines.
I purchased this boat with just built engine. All the good parts, dyno tuned, etc. 35 hours on the engines, runs great! The carburetors were used, but gone through and knew that up front, but still working on tuning properly. So now I am checking over all of my ignition and wiring. Everything looks great until I pull a distributor cap. I know this was ran in salt water, but wow, looks like they cap and rotor have 100,000 miles on them.
[ATTACH=CONFIG]556263[/ATTACH][ATTACH=CONFIG]556264[/ATTACH][ATTACH=CONFIG]556265[/ATTACH]
Looks like I may have found my problem. My guess is that with brand new plugs there was little resistance to fire them, but get a little build up on them and no- workey.
This is what i get for making assumptions. I must apologize for wasting all of your time. Thank you for all of your input.
One more question. The pickup in these MSD distributors, can I spray with a rust preventative and will they be ok, or does it look like they need replaced also?
I purchased this boat with just built engine. All the good parts, dyno tuned, etc. 35 hours on the engines, runs great! The carburetors were used, but gone through and knew that up front, but still working on tuning properly. So now I am checking over all of my ignition and wiring. Everything looks great until I pull a distributor cap. I know this was ran in salt water, but wow, looks like they cap and rotor have 100,000 miles on them.
[ATTACH=CONFIG]556263[/ATTACH][ATTACH=CONFIG]556264[/ATTACH][ATTACH=CONFIG]556265[/ATTACH]
Looks like I may have found my problem. My guess is that with brand new plugs there was little resistance to fire them, but get a little build up on them and no- workey.
This is what i get for making assumptions. I must apologize for wasting all of your time. Thank you for all of your input.
One more question. The pickup in these MSD distributors, can I spray with a rust preventative and will they be ok, or does it look like they need replaced also?
06-11-2016, 08:50 AM
#55
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iTrader: (1)
Those look almost brand new for MSD, Doh !
Yes, replace.
And yeh, if you have read even just 1 msd thread, you will see the same. Happens in fresh water too, but slower.
There is a spray some use (on new MSD parts) but I forget what......I won't deal with MSD for this (corrosion) and many other reasons.
I believe it was a CRC product. I'll try to help you find it.
Yes, replace.
And yeh, if you have read even just 1 msd thread, you will see the same. Happens in fresh water too, but slower.
There is a spray some use (on new MSD parts) but I forget what......I won't deal with MSD for this (corrosion) and many other reasons.
I believe it was a CRC product. I'll try to help you find it.
06-11-2016, 08:52 AM
#56
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I gave my distributors a coat of CRC-SP400 in 2010, when they were new. They still look new today. I replace the cap and rotor yearly.
You can remove them, take them all apart, de rust them, and coat them. If you have advance springs in them, I would take a good look at them, good chance they would be falling apart by now !
You can remove them, take them all apart, de rust them, and coat them. If you have advance springs in them, I would take a good look at them, good chance they would be falling apart by now !
06-11-2016, 08:59 AM
#57
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06-11-2016, 09:00 AM
#58
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Originally Posted by MILD THUNDER
I gave my distributors a coat of CRC-SP400 in 2010, when they were new. They still look new today. I replace the cap and rotor yearly.
You can remove them, take them all apart, de rust them, and coat them. If you have advance springs in them, I would take a good look at them, good chance they would be falling apart by now !
You can remove them, take them all apart, de rust them, and coat them. If you have advance springs in them, I would take a good look at them, good chance they would be falling apart by now !
06-11-2016, 09:25 AM
#59
Registered
Originally Posted by SB
Thanks, I no longer have to search.
https://www.google.com/webhp?sourcei...q=fluid%20film
06-20-2016, 01:10 PM
#60
Platinum Member
Platinum MemberThread Starter
Update.
I think I may have finally figured it out. I believe my problem was caused by reversion from running mufflers.
Here's the long story. After replacing cap, rotor, pickup, wires, it is time to set the timing. Start both engines and let them warm up a little. Got the timing set, of course I was revving the engine to check total advance. Only thing left was to re-calibrate the O2 sensors which had been unplugged (thank God). Pulled them out and they were dripping wet.... I have extenders on the bungs which I guess trapped the water up there. Regardless they were seeing water. It obviously doesn't revert at idle or it would never want to idle. My best uneducated guess is that at low and mid range rpms there is enough back pressure (and not enough pressure) that is causes reversion, fouling the plugs. A few more times out will tell me for sure. Damn Gibson mufflers - and they assured me there would be no issues (they have 4.5" inlets and only 4" outlets - I should have known better and sent them back). I hate these expensive learning curves.
I think I may have finally figured it out. I believe my problem was caused by reversion from running mufflers.
Here's the long story. After replacing cap, rotor, pickup, wires, it is time to set the timing. Start both engines and let them warm up a little. Got the timing set, of course I was revving the engine to check total advance. Only thing left was to re-calibrate the O2 sensors which had been unplugged (thank God). Pulled them out and they were dripping wet.... I have extenders on the bungs which I guess trapped the water up there. Regardless they were seeing water. It obviously doesn't revert at idle or it would never want to idle. My best uneducated guess is that at low and mid range rpms there is enough back pressure (and not enough pressure) that is causes reversion, fouling the plugs. A few more times out will tell me for sure. Damn Gibson mufflers - and they assured me there would be no issues (they have 4.5" inlets and only 4" outlets - I should have known better and sent them back). I hate these expensive learning curves.
