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Fuel/spark plug fouled this weekend Printed From: CorrectCraftFan.com Category: Repairs and Maintenance Forum Name: Engine Repair Forum Discription: Engine problems and solutions URL: http://www.CorrectCraftFan.com/forum/forum_posts.asp?TID=36704 Printed Date: October-07-2024 at 6:28pm Topic: Fuel/spark plug fouled this weekend Posted By: racingnc Subject: Fuel/spark plug fouled this weekend Date Posted: July-09-2015 at 6:08pm Quick question. I put a 542 on my 1986 ski Martinque it has a 351 reverse rotation engine with electronic ignition. I gap my plugs at .035 every year when I replace them. My timing is set per the manual at 10° btc. I had about 15oo lbs of weight on Saturday. Long story short plug 8 and plug 3 fouled. I have never asked the question if I should adjust the timing to compensate for the loss of rpm. My old prop was running wot 5800 rpm my 542 only runs wot to 4800 rpm. With that big of an rpm change should the timing be changed if to to what degree? Replies: Posted By: phatsat67 Date Posted: July-09-2015 at 6:40pm Nothing. The engine only needs all of its timing by 3000 RPMS. Timing spec doesn't change after that. It's probably blowing fuel out of the carburetor when it shouldn't. ------------- Posted By: MrMcD Date Posted: July-09-2015 at 7:20pm I would do a compression check to see why those two cylinders fouled. I think the Higher RPM was masking an existing issue. Posted By: SNobsessed Date Posted: July-09-2015 at 10:29pm A leak down test might be valuable too. I had some plug fouling & turned out to be valve stem seals leaking.     ------------- “Beer is proof that God loves us and wants us to be happy.” Ben Franklin

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