1998 mercury bigfoot 4 stroke sputtering
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=49763
Printed Date: October-05-2024 at 6:40pm
Topic: 1998 mercury bigfoot 4 stroke sputtering
Posted By: Wheelers4life2
Subject: 1998 mercury bigfoot 4 stroke sputtering
Date Posted: April-21-2021 at 12:31pm
| I have had this boat for almost 2 years and it has been in the shop multiple times. I can take it off the trailer and run it all day long. Sometimes 2 days in a row. Then all of the sudden after sitting for a while fishing it is hard to start and when it does start it will idle rough and kick and sputter unless I get it above 3500 rpms. Then the next day it will run great all day long. So the mechanic have did a compression check and said all 4 are at 180. Carbs rebuilt, fuel pump and all fuel lines including primer bulb has been replaced. New portable tank. New spark plugs and fuel filter as well. Coils have been checked. Just cannot figure out what is going on. |
Replies:
Posted By: 8122pbrainard
Date Posted: April-21-2021 at 1:06pm
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Danny, I have a feeling you have confused CCfan with another web site. CCfan is primarily inboard engines. ------------- /diaries/details.asp?ID=1622" rel="nofollow - 54 Atom /diaries/details.asp?ID=2179" rel="nofollow - 77 Tique 64 X55 Dunphy Keep it original, Pete < |
Posted By: Jonny Quest
Date Posted: April-21-2021 at 3:45pm
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Now, now, now, Pete -- be nice. We don't want to run the new kid off... This group of gear-heads has a vast knowledge of most things "marine" so I'm not surprised to see a few non-inboard questions. I wouldn't be surprised if several CCF members had a previous boat with a Merc outboard on it...yours truly included. I had a "barefoot" style boat built by Marlin in Oregon. 200HP Merc Black Max. I sold that boat to buy my 1994 SNOB. Take an in-line spark tester with you. My old Merc O/B could get a bit grumpy on start-ups and I finally traced the problem to coils, plug wires and associated connections. You stated that the coils have been checked, but have they been replaced? I would also replace spark plug wires. JQ ------------- Current 2003 Ski Nautique 206 Limited Previous 2001 Ski Nautique Open Bow 1994 Ski Nautique Open Bow Aqua skiing, ergo sum |
Posted By: Wheelers4life2
Date Posted: April-21-2021 at 9:41pm
No the coils have not been replaced. I just got one coil in yesterday. The other is on back order. I am going out Sunday. I have changed the plugs this afternoon, and cleaned out the tank and will purchase fresh fuel before I go out. I do not have a spark tester right now I will order one. I will take the tools and the new coil out with me if it does it again I will replace one of the two coils and see if that does the trick. The crazy thing is that it only does when it feels like it. I know that sound crazy but I can go out three times and nothing. Then it happens or I can go out three times in a row where it does it every time. I have spent so much money at the shops that I am on the verge of purchasing a new outboard. Thanks
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Jonny Quest wrote:Posted By: SNobsessed
Date Posted: April-22-2021 at 7:54am
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The ignition module can be intermittant too. Circuit boards can get micro cracks & randomly fail then re-heal for a while. Best way to test for this is to have a known good replacement at time of failure (althought the connector can be bad & fool you when touched). This is where the shop with spare part has an advantage. Electrical modules are generally not returnable for obvious reasons. Good luck ------------- “Beer is proof that God loves us and wants us to be happy.” Ben Franklin |
Posted By: Mpost
Date Posted: April-22-2021 at 9:15am
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I have seen this type of symptom and fixed it on 3 different vintage Merc/Mariners. All were intermitent circuit boards that feed the coil packs for spark. My 60HP Mariner took me 2 weeks of testing multiple times a day to narrow it down to one of the boards and not a coil. I used a timing light to determine I was getting no spark off one plug wire when it failed. Swapped coils, no difference. Swapped boards and it moved. ------------- 84 SN Sold 98 SN Lund Pro V 1975 Alumacraft |
Posted By: Jonny Quest
Date Posted: April-22-2021 at 4:03pm
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+ 1 on the ignition module. I forgot that the “fix” on my old Black Max included an ignition module. JQ ------------- Current 2003 Ski Nautique 206 Limited Previous 2001 Ski Nautique Open Bow 1994 Ski Nautique Open Bow Aqua skiing, ergo sum |
Posted By: Wheelers4life2
Date Posted: April-23-2021 at 9:46am
| Where are the circuit boards. I will take tools with me to the lake |
Posted By: Mpost
Date Posted: April-23-2021 at 10:08am
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Look up your motor i the link below by serial number and check under electrical components. different years they are called different things. Later models look to call it the ECM. https://www.mercurymarine.com/en/us/parts-and-accessories/parts-catalog" rel="nofollow - MERC ------------- 84 SN Sold 98 SN Lund Pro V 1975 Alumacraft |
Posted By: Wheelers4life2
Date Posted: April-23-2021 at 11:16am
Ok yeah I got you know. Thanks |
Posted By: Wheelers4life2
Date Posted: April-28-2021 at 6:08pm
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I spoke with an older mechanic today that said he would bet that it would be the stator. could this be what is going on the low rpm coils on the stator breaking down. Thanks
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