Dirty exhaust
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=49115
Printed Date: May-20-2024 at 5:35am
Topic: Dirty exhaust
Posted By: Mikeski2000
Subject: Dirty exhaust
Date Posted: August-19-2020 at 11:23pm
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I have a 2000 Ski Nautique with the 5.0 Gm throttle body fuel injection system. I get a lot of dark soot on my transom after skiing. I run 91 octane fuel and put a bottle of sea foam in every couple tanks. Every 50 hrs or so I have to clean my plugs because they get fairly fouled by then. I do a new cap and plugs every season, or about every 100 hrs. The perfect pass says 800 hrs (300 by me) but it might be more. My gauges failed so I replaced them when I got the boat 4 years ago. I am not an gear head but I’m handy. What does my engine need, or is it heading to the train station ( Yellow Stone reference). If it needs replaced how much, if any of the parts can be re used on a 5.7 if I re power it. It still runs really well, pulls nice through the course and holds speed it’s just a bit of a dog out of the hole and tops out at 41mph Sorry for being long winded. Mike ------------- Mike |
Replies:
Posted By: GottaSki
Date Posted: August-20-2020 at 7:01am
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Are you running without a tstat? ------------- "There is nothing, absolutely nothing, half so much worthwhile as messing around with boats...simply messing." River Rat to Mole |
Posted By: SNobsessed
Date Posted: August-20-2020 at 7:51am
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Could also be dirty or leaking injector.
------------- “Beer is proof that God loves us and wants us to be happy.” Ben Franklin |
Posted By: Mikeski2000
Date Posted: August-20-2020 at 8:48am
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It has a new 170 thermostat in there last year the old one would not let it get above 135 or so. I have cleaned up the throttlebody a couple times with throttlebody cleaner and I run fuel injector cleaner through the gas is the fuel injector something I would be able to work on myself ------------- Mike |
Posted By: Jonny Quest
Date Posted: August-20-2020 at 10:56pm
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You only need 89 octane fuel...not 91. It is a myth that "premium" fuel makes your engine run better. That MAY contribute a little to your soot problem as higher octane fuel burns slower than lower octane fuels. What spark plug are you running? If the plug is too cold, that can cause soot in the exhaust As stated above, I would first look for a bad injector that is not properly atomizing the fuel and/or leaking. If your EFI engine has a mass air flow sensor, make sure it is properly cleaned. JQ ------------- Current 2003 Ski Nautique 206 Limited Previous 2001 Ski Nautique Open Bow 1994 Ski Nautique Open Bow Aqua skiing, ergo sum |
Posted By: Mikeski2000
Date Posted: August-20-2020 at 11:55pm
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That’s interesting about the fuel. Most places I fuel up the only non ethanol option is 91. They are the mr43lts. they are the Plug calles out in the manual. ------------- Mike |
Posted By: Jonny Quest
Date Posted: August-21-2020 at 10:49am
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Mike: bad injector(s) is the most likely culprit. In my old 1994 SN, I had the throttle-body Electronic Fuel Injection and one of the injectors was dribbling quite badly. That produced a lot of dark gray to black smoke that wound up on my transom after every trip. The engine would load up on too much fuel at lower RPMs. High RPM was OK. JQ
------------- Current 2003 Ski Nautique 206 Limited Previous 2001 Ski Nautique Open Bow 1994 Ski Nautique Open Bow Aqua skiing, ergo sum |
Posted By: Mikeski2000
Date Posted: August-21-2020 at 12:09pm
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Ok that makes a A lot of sense. The exhaust is bad or really dark especially after pulling my kids knee boarding or skiing under 20 mile an hour I Rarely see it when slaloming. Are the injectors marine specific or can I get them at auto zone or the like. Thanks Mike ------------- Mike |
Posted By: Jonny Quest
Date Posted: August-21-2020 at 12:38pm
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Pull out an injector and look it up. I use www.RockAuto.com. It shouldn’t be marine specific. I would change them all out at the same time. Don’t go cheap and try to save a few buck$ — put in good quality injectors. JQ ------------- Current 2003 Ski Nautique 206 Limited Previous 2001 Ski Nautique Open Bow 1994 Ski Nautique Open Bow Aqua skiing, ergo sum |
Posted By: Mikeski2000
Date Posted: August-21-2020 at 1:05pm
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You bet after 20 years I’m sure they’re both due. ------------- Mike |
Posted By: Mikeski2000
Date Posted: August-29-2020 at 6:47pm
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I replaced both of my injectors. The service manager that I talk to said another problem might be my O2 sensor or oxygen sensor. He thinks those may cause it to run to Rich as if it were at altitude. I haven’t run it yet but I wonder if I should look into that as well ------------- Mike |
Posted By: KENO
Date Posted: August-29-2020 at 11:22pm
Does this mean you replaced both injectors and you're still getting the same dirty exhaust? Looking for an O2 sensor on your engine would be like looking for a non existent needle in a giant haystack.  I think you should talk to somebody besides the service manager, since he thinks you have an O2 sensor on a Model year 2000 TBI Pleasurecraft marine engine. And..............nowhere near the train station or at least it shouldn't be.
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Mikeski2000 wrote:Posted By: Mikeski2000
Date Posted: August-30-2020 at 1:06pm
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I’m going to water test today. Ran great on the hose, and looked like it was spraying well. Service manager was thinking 94 Chevy truck, since that’s how we found the part number for my injectors. I say boat and I get a Deere in the headlight look or they tell me they can’t help me at all ------------- Mike |
Posted By: gun-driver
Date Posted: September-03-2020 at 10:11am
Is this the” Deere “in the headlights look you got   |
Posted By: Mikeski2000
Date Posted: September-03-2020 at 12:13pm
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It’s always “I can’t look up a boat! We don’t carry any boat parts. Have you tried the marina?” My marina services jet skis and pontoons. Everything else is guess work ------------- Mike |
Posted By: Mikeski2000
Date Posted: September-05-2020 at 9:18am
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Just got back from the lake. Had a lot of hesitation when I punch it and lost 2 to 2½ mph of the top end. Didn't respond well to PP at 34 mph. Was up and down not holding speed at all. The injector tip on the replacement was about an ⅛" shorter than the original. Now to see if I can find the right ones. ------------- Mike |
Posted By: Mikeski2000
Date Posted: September-25-2020 at 11:27pm
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Looking at a different option on injectors. My GM 305 tbi replacement injectors were not functional. Thinking about refurbished injectors from rock auto or a complete replacement like this. https://www.ebay.com/itm/Motor-Man-5235279-TBI-Fuel-Injector-Kit-Regulator-GMC-Chevrolet-5-0L-305/292963979289?epid=74260124&hash=item4436039019:g:xloAAOSwFlNcZteD Sorry I made this ridiculous link. Can’t figure out how to shorten it ------------- Mike |
Posted By: Mikeski2000
Date Posted: October-03-2020 at 2:23pm
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Finally got good injectors. Just water tested and it ran really smoothly. A lot less gas smell in the exhaust and transom is clean. Oh and my son ran 6 slalom sets in 45 deg air. Great day ------------- Mike |
Posted By: MechGaT
Date Posted: October-04-2020 at 3:01pm
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Glad you got it figured out. ------------- '92 Sport Nautique |