Plugs for Crappy Gas
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=6860
Printed Date: January-17-2025 at 8:56pm
Topic: Plugs for Crappy Gas
Posted By: sjpitts
Subject: Plugs for Crappy Gas
Date Posted: May-28-2007 at 6:21pm
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I have an 89 PCM 351 with a Holley 4160 carb. It has started sputtering/backfiring under load so I am going give it a bit of a tune up.
The PCM recommended plug is an autolite 24. Currently, the boat has AC Delco R43TS plugs installed. They were installed last spring by the local boat mechanics (who are very well respected) before I knew anything about the boat. These plugs are one step hotter then the recommended Autolites. I have some vague recollection that the hotter plugs were used to help compensate for all the crap (i.e., ethanol) that is in gas these days. Does that make any sense? Anybody believe this? Alternatively, could the hotter plugs be better for a well worn engine (750 hours) that may have low compression on one side? I already have some autolite 24s I bought at wally world last year. Should I install them, or stay with the hotter plug? I also have a set of PCM plug wires and a new condensor courtesy of SkiDim. I am hoping this is going to solve my sputter problem. Thanks Jared And I am sorry if the "which plugs" question is asked all the time. I searched for ethanol and didn't find anything related to plugs, so I don't think anyone has asked this particular question before. |
Replies:
Posted By: boat dr
Date Posted: May-28-2007 at 6:31pm
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Jared, sroll down and you will see a post on a simular topic,read that thread and you make up your own mind........
Put the stuff back in that came out,AC=GM.....Autolite=Ford........boat dr ------------- boat dr /diaries/details.asp?ID=4631 - 1949 Dart /diaries/details.asp?ID=1533 - 1964 American Skier |
Posted By: sjpitts
Date Posted: May-28-2007 at 6:59pm
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Thanks Boat Dr.
I certainly agree that going with what PCM recommended is a good idea. That is why I bought the autolite 24s in the first place (when I realized the boat mechanics had installed the non-standard plugs) But I am still curious about the "hotter-plug-for-ethanol" theory. I doubt that PCM had ethanol in mind when they designed the engine. If a person wanted hotter plugs and wanted to stay with autolite (which also seems like a good idea) couldn't they go with the autolite 25s? But now that I write this, I think it is probably a bad idea. Better to start with what PCM recommended. Maybe the hotter plugs are part of my sputter/backfire issue. So I will take your advice and go with the autolite 24s Thanks again Jared |
Posted By: boat dr
Date Posted: May-28-2007 at 7:18pm
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Jared ,I am not a slow learner,rather the contrary, I am a fast "forgetter"
And when I start to second guess the people that made this STUFF,I am doomed to running in circles .Getting no boats out of my shop[ and putting out fires that I started.................HELLO ------------- boat dr /diaries/details.asp?ID=4631 - 1949 Dart /diaries/details.asp?ID=1533 - 1964 American Skier |
Posted By: GottaSki
Date Posted: May-29-2007 at 7:24am
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I run the CR43TS, I like them a lot andd they are not hotter than the autolite 24's, they are a direct match.
Change plugs if you want, but look elsewhere for your root problem. ------------- "There is nothing, absolutely nothing, half so much worthwhile as messing around with boats...simply messing." River Rat to Mole |
Posted By: 79nautique
Date Posted: May-29-2007 at 8:42am
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yea like get rid of the points and replace the power valve. ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=756&sort=&pagenum=1&yrstart=1979&yrend=1979 - 79 nautique |
Posted By: boat dr
Date Posted: May-29-2007 at 8:49am
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GottaSki,you seem to have a lot of knowledge about this engine thing, and I tip my hat to you on a lot I have learned from you, thanx.
But, the CR43TS,those fit a lot of the M/Cruiser - GM engines,I try to run only the MR's they have a S/S barrel, and seem to not gall as bad as the CR's.....JMHO...boat dr ------------- boat dr /diaries/details.asp?ID=4631 - 1949 Dart /diaries/details.asp?ID=1533 - 1964 American Skier |
Posted By: GottaSki
Date Posted: May-29-2007 at 9:39am
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Dr, thanks, for the kind words
Ah Yes, my next batch will also be ss, either Autolite or AC; I see the std Autolite 24's are not ss either. AR24's would be the SS autolite number, their site indicates. and my humbling err, apparently there is a heat range difference just as he indicated. ------------- "There is nothing, absolutely nothing, half so much worthwhile as messing around with boats...simply messing." River Rat to Mole |
Posted By: sjpitts
Date Posted: May-29-2007 at 10:02am
Just to clarify-- the stainless Autolite 24's are numbered AR24? They are otherwise the same as the recommended "normal" 24s? I thought 24s were 24s, and everything else was different. Are stainless AR24s worth the difference? Even if you end up replacing them every year or two? Jared |
GottaSki wrote:Posted By: sjpitts
Date Posted: May-29-2007 at 10:06am
I am afraid of that. I am going to start a new thread on my sputtering/backfiring problem. Jared |
Posted By: GottaSki
Date Posted: May-29-2007 at 10:15am
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yes,
yes, I think so, and the price difference is minimal. Yes, 2-3 seasons are typical. Plugs only go bad early when something else is amiss. One can Compare the autolite models here: http://www.autolitesparkplugs.com/search_char.asp?threadSize=14mm&hexSize=5%2F8%22+%2816mm%29&gap=&seatType=tapered&terminalType=&heatRange=4&reach=11.6mm+%28.460%22%29&resistor=yes&action.x=58&action.y=13 crap, doesn't work ------------- "There is nothing, absolutely nothing, half so much worthwhile as messing around with boats...simply messing." River Rat to Mole |
Posted By: boat dr
Date Posted: May-29-2007 at 11:00am
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Tom, not here to condemn anyone, just try to share what little bit I know .Would like to talk to you tho, Am close to putting this stroker back in the water, have made several changes,cerb, Hi-Teks ECT. And want all the systems working fine before Green Lake.
There will be some BIG GUNS THERE<318-386-2825.........billy ------------- boat dr /diaries/details.asp?ID=4631 - 1949 Dart /diaries/details.asp?ID=1533 - 1964 American Skier |
Posted By: KyleT
Date Posted: May-29-2007 at 12:25pm
| IM having the same issue. intermittant hesitation and backfire. |
Posted By: GottaSki
Date Posted: May-29-2007 at 8:53pm
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billy I tried calling tonight, that must be the shop. Calling midday is tough, I sent an email address
Kyle a stumble-pop is typically... not enough initial timing sloppy accel pump air screws set too lean clogged idle circuit (fuel) ------------- "There is nothing, absolutely nothing, half so much worthwhile as messing around with boats...simply messing." River Rat to Mole |
Posted By: wannabeSS
Date Posted: May-29-2007 at 9:37pm
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Just want to add that you should be careful with getting hotter plugs, easier way to get detonation. ------------- 96 Camaro SS #1157 84 Ski Nautique, fat sacks, fly high pole 06 LF Fish 125 06 LF PS3 137 |
Posted By: KyleT
Date Posted: May-30-2007 at 6:34pm
ok, is there a site or page that has some info on the engine settings and recommendations? for timing ect... Ill look at the other 3 things. |
Posted By: KyleT
Date Posted: May-30-2007 at 6:35pm
| oh yeah, once it gets going a little faster, ie cruise speed ect. it runs great and has lots of power. |