'95 Ski GT-40 question
Printed From: CorrectCraftFan.com
Category: General Correct Craft Discussion
Forum Name: General Discussion
Forum Discription: Anything Correct Craft
URL: http://www.CorrectCraftFan.com/forum/forum_posts.asp?TID=35916
Printed Date: September-26-2024 at 1:51pm
Topic: '95 Ski GT-40 question
Posted By: mdvalant
Subject: '95 Ski GT-40 question
Date Posted: April-30-2015 at 3:16pm
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Hey gang! Our new to us 95 Ski seems to be, for lack of better term, "chugging" at WOT. The best way I can describe it is compared to a carbed motor not all 4 barrels opening up. It's up around 42-43mph at 4600 rpm running a 654 ACME 12.5X15. It's right there, but feels just a tiny tiny bit short of what it should be. I'd assume the basics..plugs/wires (not sure when those were done last) but didn't know if you guys had any secrets on these GT's. Fuel could also be to blame I suppose. Haven't run a fresh brand new tank all the way through yet this year. ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=5009 - '90 Ski (sold) http://www.correctcraftfan.com/diaries/details.asp?ID=5479 - '00 Sport Mississippi River - Bellevue, IA |
Replies:
Posted By: Gary S
Date Posted: April-30-2015 at 3:29pm
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I think Zach has mentioned before that the caps and rotor can have issues, so change that too. ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=1711&sort=&pagenum=1&yrstart=1966&yrend=1970" rel="nofollow - 69 Mustang HM SS 95 Nautique Super Sport |
Posted By: Fl Inboards
Date Posted: April-30-2015 at 3:55pm
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what rpm's are you running when starts to chug ? ------------- Hobby Boats can be expensive when the hobbyist is limited on their own skill and expertise. 1993 Shamrock "fat" 20. 2008 Nautique 196 5.0 |
Posted By: mdvalant
Date Posted: April-30-2015 at 3:56pm
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4600 RPM. When it's not chugging or trying to open up itll bump up to 4700 and I think it wants to do 4800 but won't get there. ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=5009 - '90 Ski (sold) http://www.correctcraftfan.com/diaries/details.asp?ID=5479 - '00 Sport Mississippi River - Bellevue, IA |
Posted By: Hollywood
Date Posted: April-30-2015 at 3:59pm
Come back after you get a few gallons of fresh gas through it. Certainly wouldn't hurt to inspect the cap & rotor. ------------- |
mdvalant wrote:Posted By: mdvalant
Date Posted: April-30-2015 at 4:00pm
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We have practice tomorrow night and Sat AM so we'll run a bunch through it then and I can report back. I'd assume that's what's up...or hope anyways :) I know the GT's had a little thing about the chug situation I guess so thought I'd check. And I'm bored at work and like to talk about Nautiques ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=5009 - '90 Ski (sold) http://www.correctcraftfan.com/diaries/details.asp?ID=5479 - '00 Sport Mississippi River - Bellevue, IA |
Posted By: TRBenj
Date Posted: April-30-2015 at 4:02pm
| That early gt40 in that hull should pull a 654 to 5200 and at least 46mph. You're a good ways off those numbers, something's up. |
Posted By: mdvalant
Date Posted: April-30-2015 at 4:03pm
woah...I was wondering what top RPM should be, Tim. Is that safe to run 5200? If it ever got there? Can't remember what the desired top is on those. If that's the case...then yes I'd say something is up. ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=5009 - '90 Ski (sold) http://www.correctcraftfan.com/diaries/details.asp?ID=5479 - '00 Sport Mississippi River - Bellevue, IA |
Posted By: MrMcD
Date Posted: April-30-2015 at 4:09pm
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I would change the fuel filter or filters if this boat is new to you and you don't have the history. If you are going to run it and burn through a tank of fuel I like to add a quart of automatic Transmission fluid to the fuel tank. ATF has many cleaning and lubricating properties that help clean a fuel injection system. It keeps the injectors snapping the way they should. I only do this once per season. You might wish to put a fuel pressure gauge on it when you run it and see how the pressure is holding up when your power falls off. The 95 has a temp sender and an oil pressure sender that can put your engine into limp mode if they go off at the wrong time. My coolant sender started making my engine stumble when the raw water pump was not putting out enough water to keep the temp constant. I guess I should be appreciative since I was able to fix it with no damage done. I run a Acme 224 Prop and RPM above 5,000 RPM and top speed of 48. |
Posted By: phatsat67
Date Posted: April-30-2015 at 4:14pm
My thoughts exactly with a 654 ------------- |
Posted By: TRBenj
Date Posted: April-30-2015 at 4:26pm
| 4800-5000 is optimal for best all around performance but 5200 won't hurt it. |
Posted By: mdvalant
Date Posted: April-30-2015 at 4:53pm
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Thanks guys! I was wondering what top RPM should be on that thing. ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=5009 - '90 Ski (sold) http://www.correctcraftfan.com/diaries/details.asp?ID=5479 - '00 Sport Mississippi River - Bellevue, IA |
Posted By: MrMcD
Date Posted: April-30-2015 at 4:59pm
| When the GT40 is running good it is pretty impressive for a stock engine. |
Posted By: mdvalant
Date Posted: April-30-2015 at 5:01pm
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I've always been a fan of the GT40's. Seems so strong. Mark, side note, your boat and trailer combo is in my top 5 Nautique favorites. You can't beat red black and white on the water. ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=5009 - '90 Ski (sold) http://www.correctcraftfan.com/diaries/details.asp?ID=5479 - '00 Sport Mississippi River - Bellevue, IA |
Posted By: mdvalant
Date Posted: April-30-2015 at 5:05pm
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Hey Mark, you say you run a 224 prop. We run a 1442 on our Sport Nautique and the tranny knocks or dampener plate makes a little tick at idle with that thing. Does the 224 do that to you? ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=5009 - '90 Ski (sold) http://www.correctcraftfan.com/diaries/details.asp?ID=5479 - '00 Sport Mississippi River - Bellevue, IA |
Posted By: TRBenj
Date Posted: April-30-2015 at 5:12pm
The tick is caused by the damper being worn or the idle needs to be adjusted, even if it only shows up with a particular prop, it is not the true cause.
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Posted By: mdvalant
Date Posted: April-30-2015 at 5:14pm
Interesting...Sporty only has about 140 hours on it! Doesn't do that on any other prop was kind of my thinking.. ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=5009 - '90 Ski (sold) http://www.correctcraftfan.com/diaries/details.asp?ID=5479 - '00 Sport Mississippi River - Bellevue, IA |
Posted By: Hollywood
Date Posted: April-30-2015 at 5:29pm
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The bigger diameter of the 1442 combined with the high pitch could be just loading the drivetrain enough to lower the RPM and then rattle. ------------- |
Posted By: mdvalant
Date Posted: April-30-2015 at 5:31pm
This is what I've been told in the past, HW. That 224 has even more pitch than the 1442 so that's why I asked about it. ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=5009 - '90 Ski (sold) http://www.correctcraftfan.com/diaries/details.asp?ID=5479 - '00 Sport Mississippi River - Bellevue, IA |
Posted By: Fl Inboards
Date Posted: April-30-2015 at 5:33pm
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In the mid 90's we had some 3/8" fuel hose that the inner liner tended to collapse on the suction side of the fuel delivery system. If it has it's original fuel lines in it I would be prone to go completely through the fuel system from the pick up tube and anti siphon fitting forward, inspecting and changing out the original fuel supply and return hoses, and checking that the vent hose was clear as well as the vent. along with a quick tear down of both fuel pumps, especially the low pressure pump as gradew seems to accumulate in the screen in the top of the pump. ------------- Hobby Boats can be expensive when the hobbyist is limited on their own skill and expertise. 1993 Shamrock "fat" 20. 2008 Nautique 196 5.0 |
Posted By: mdvalant
Date Posted: April-30-2015 at 5:35pm
You're killin me Jody. hahahaha Thanks for that, I think   ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=5009 - '90 Ski (sold) http://www.correctcraftfan.com/diaries/details.asp?ID=5479 - '00 Sport Mississippi River - Bellevue, IA |
Posted By: lewy2001
Date Posted: April-30-2015 at 10:06pm
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Fuel pressure check....... The early 95 GT40 without the FCC should still have a "Schrader" valve on fuel rail. ------------- If you're going through hell, keep going http://www.correctcraftfan.com/diaries/details.asp?ID=2999" rel="nofollow - 89 Ski <a href="http://www.correctcraftfan.com/diaries/details.asp?ID=5685" ta |
Posted By: Gary S
Date Posted: April-30-2015 at 10:50pm
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On a side note Mark, Skidim is listing new for '15, PCM ECM's for all GT40 efi engines at $572.69 ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=1711&sort=&pagenum=1&yrstart=1966&yrend=1970" rel="nofollow - 69 Mustang HM SS 95 Nautique Super Sport |
Posted By: Toertel
Date Posted: May-01-2015 at 12:34am
Since we have a GT-40 in the Sport I'm following this post in order to be potentially prepared if things go south. Is the ATF idea good? Thoughts ? Sorry to jump off topic but this. caught my attention ------------- 1994 Sport Nautique |
Posted By: mdvalant
Date Posted: May-01-2015 at 12:35am
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I too was wondering what everyone's thoughts were on the ATF idea. ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=5009 - '90 Ski (sold) http://www.correctcraftfan.com/diaries/details.asp?ID=5479 - '00 Sport Mississippi River - Bellevue, IA |
Posted By: lewy2001
Date Posted: May-01-2015 at 2:01am
I had a lot of fun with my ECM project for the GT40. I started it thinking that down the road I may build a stroker engine. I run the DIYPNP ECM all the time now and I am continually analysing and updating the tuning. ------------- If you're going through hell, keep going http://www.correctcraftfan.com/diaries/details.asp?ID=2999" rel="nofollow - 89 Ski <a href="http://www.correctcraftfan.com/diaries/details.asp?ID=5685" ta |
Posted By: 8122pbrainard
Date Posted: May-01-2015 at 7:40am
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I would rather see Marvel Mystery added to the gas than ATF. Both are very similar with being heavy on detergents but the Marvel is designed as a top cylinder lube. The ATF is more on the hydraulic oil side. ------------- /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: Toertel
Date Posted: May-01-2015 at 9:25am
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Thanks Peter! So if I would consider doing it, then with Marvel, but is this needed or a preventative thing to do? Saw this come up theb1st time in this post. ------------- 1994 Sport Nautique |
Posted By: JoeinNY
Date Posted: May-01-2015 at 9:48am
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Fuel injector cleaner costs about the same as atf last I checked. ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=1477 - 1983 Ski Nautique 2001 1967 Mustang 302 "Decoy" http://www.youtube.com/watch?v=cO5MkcBXBBs - Holeshot Video |
Posted By: gun-driver
Date Posted: May-01-2015 at 11:31am
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I've heard of guys running ATF and Jet-A in diesels for clean up but not in gassers doesn't mean it can't be done just never heard of it till now. As for the GT -40 I run the 1442 runs 48 - 49 and will spin it up to 5200 and I'll run It there for a long time getting down the lake. Won't hurt a healthy 351 |
Posted By: mdvalant
Date Posted: May-01-2015 at 11:33am
It's our team boat so it'll be pulling quite a few footers every now and then and I would LOVE to see 48-49.! ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=5009 - '90 Ski (sold) http://www.correctcraftfan.com/diaries/details.asp?ID=5479 - '00 Sport Mississippi River - Bellevue, IA |
Posted By: MrMcD
Date Posted: May-01-2015 at 3:53pm
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In the early 90's I ran into many Fuel Injection issues, one of the products my company owned was Carter and at that time we had injectors and fuel pumps we manufactured and sold. I called on literally thousands of shops. Some Fuel Injection cleaners caused more problems than they solved in those early years. I am sure they are better now but I never saw an issue with ATF. Most of the Diesel guys ran ATF as a fuel injector lubricant. Not with every tank but occasionally they would drop in ATF for the lubrication and cleaning of Fuel Injectors. To date I have never heard a complaint related to it's use. If your vehicle had a Catalytic converter I would cut back to 1/2 QT rather than a full quart.. On a boat I would add the ATF after putting in the fuel and drive it around to mix it up and than forget about it and let it do its job. Since hearing this in the 90's I have used it many times in all my vehicles that are fuel injected and shared it with many shops and friends when they had rough idle issues. It works very well. Marvel may work equally well or better but I have no experience with Marvel. I did add Marvel to my oil in my Diesel when I was in extremely cold area's, -7 with a 30 mile headwind made cold starts near impossible for a guy not used to that. The Marvel helped a lot, it helped the engine oil not thicken as much and the engine turned over much faster on the cold start. I have heard that Marvel is a very highly refined Oil, I have not heard it has cleaning additives. |
Posted By: rebel skier
Date Posted: May-01-2015 at 4:17pm
| So what type of ATF do you run through it? |
Posted By: MrMcD
Date Posted: May-01-2015 at 5:00pm
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I buy the low price ATF at walmart, it is around $9.00 for a gallon, makes cheap injector cleaner. I do not think it would help a carburetor. I have been told that the Ford ATF has more lubricants in it than the GM ATF but most sold now says it is compatible with both. Thanks for the kind words about the color, we are happy with it. The trailer looks good and tows well but it did a lousy job of keeping the boat on the trailer in an accident last year, posted on here last August, since repaired and upgraded for safety. The 224 I purchased from Tim and I have been happy with it. It does not give any noise at idle and is quiet at wakeboard speeds compared to the OJ 3 and 4 blades I have, and it outperforming the OJ's at low and high speed. I would like to play with other props but the cost makes me happy with what I have so Thanks to TIm, TRBENJ for good advice on this prop. Once last summer with one person aboard, premium fuel and a garmin GPS and smooth water with the Bimini top down it ran a touch over 50 mph at 5,200-5,300 RPM. Normally is does not pull that high but that day it was good. |
Posted By: mdvalant
Date Posted: May-04-2015 at 11:34pm
Hey guys, So...this may sound stupid but I can't find the fuel filter on this thing. Help? ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=5009 - '90 Ski (sold) http://www.correctcraftfan.com/diaries/details.asp?ID=5479 - '00 Sport Mississippi River - Bellevue, IA |
Posted By: gun-driver
Date Posted: May-05-2015 at 12:38am
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Should be between the tank and the low pressure pump along the left main stringer. You can see where mine is in the bottom left of the picture. http://s256.photobucket.com/user/gun-driver/media/95%20Nautique%20pictures/IMG_0786.jpg.html" rel="nofollow"> 
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Posted By: MrMcD
Date Posted: May-05-2015 at 4:32am
| Gun Driver your boat is really clean. Looking good. |
Posted By: mdvalant
Date Posted: May-05-2015 at 11:15am
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Thanks Paul!!! That helps a ton. Just what I needed! I also found this (with windshield washer hoses on it apparently) Edit: Ok, I quit, can't get my pics to link anymore    ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=5009 - '90 Ski (sold) http://www.correctcraftfan.com/diaries/details.asp?ID=5479 - '00 Sport Mississippi River - Bellevue, IA |
Posted By: gun-driver
Date Posted: May-05-2015 at 12:01pm
Thanks Mark. With two kids (8 & 4) and a dog it's an up hill battle to keep her clean. |
Posted By: gun-driver
Date Posted: May-05-2015 at 12:03pm
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Mike I have no idea what that is see if you can track it to the ends and maybe we can figure out what it's for. |
Posted By: jhersey29
Date Posted: May-05-2015 at 12:47pm
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It is a fuel filter inline as part of the vacuum system. Evinrude part Filter-Fuel-398327 |
Posted By: lewy2001
Date Posted: May-05-2015 at 8:37pm
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That is the vacuum line for the MAP sensor. ------------- If you're going through hell, keep going http://www.correctcraftfan.com/diaries/details.asp?ID=2999" rel="nofollow - 89 Ski <a href="http://www.correctcraftfan.com/diaries/details.asp?ID=5685" ta |
Posted By: gun-driver
Date Posted: May-05-2015 at 10:13pm
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That's strange as mine doesn't have one My bad it looks like I do have one. Funny I don't remember that when I did the referb. http://s256.photobucket.com/user/gun-driver/media/95%20Nautique%20pictures/DSC00334.jpg.html" rel="nofollow"> 
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Posted By: jhersey29
Date Posted: May-05-2015 at 10:18pm
| I find the part somewhat odd. The vacuum from the engine would suck air from the map sensor not push it so what the heck is a fuel filter need for. Maybe they put it in for some rare case where the engine backfires and blows gas into the vacuum tube and it would make it all the way to the map sensor and kill it. Under normal conditions the vacuum would be pulling on the map sensor so all you are doing is filtering the sucking from the map sensor to the upper intake manifold. The part also has an arrow on it telling direction but by playing with the part in my tool box I don't see much of a difference. |
Posted By: mdvalant
Date Posted: May-05-2015 at 10:24pm
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Good news, I found the real fuel filter! right next to the stringer where it was mentioned, so thank you for the help!!! About that little inline filter........ Do you guys think i should remove it, or think it may have anything to do with my top end/RPM issues? I ordered my new real fuel filter today. ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=5009 - '90 Ski (sold) http://www.correctcraftfan.com/diaries/details.asp?ID=5479 - '00 Sport Mississippi River - Bellevue, IA |
Posted By: jhersey29
Date Posted: May-05-2015 at 10:25pm
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I see the filter in your picture. You have one - Gun-Driver . |
Posted By: jhersey29
Date Posted: May-05-2015 at 10:27pm
It has nothing to do with much of anything other than if your having a vacuum leak and their is a crack in that filter. Leave it alone. My 99 has one, 97 buddies has one, and other buddies 01 has it. |
Posted By: Gary S
Date Posted: May-05-2015 at 10:49pm
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I never noticed one on mine either,I'll have to look but because my engine is bacerds its not as easy to see in there. ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=1711&sort=&pagenum=1&yrstart=1966&yrend=1970" rel="nofollow - 69 Mustang HM SS 95 Nautique Super Sport |
Posted By: mdvalant
Date Posted: May-05-2015 at 10:55pm
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Next question... What spark plugs are you guys running in your GT40s? ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=5009 - '90 Ski (sold) http://www.correctcraftfan.com/diaries/details.asp?ID=5479 - '00 Sport Mississippi River - Bellevue, IA |
Posted By: mdvalant
Date Posted: May-14-2015 at 2:47pm
So, Max RPM in the GT40 manual states 4800... New plugs and new fuel filter installed...I'm running about 4750 with the ACME1442 now at 44mph It's still not "right" to my standards...feels weird up there but maybe that's just how it is ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=5009 - '90 Ski (sold) http://www.correctcraftfan.com/diaries/details.asp?ID=5479 - '00 Sport Mississippi River - Bellevue, IA |
Posted By: gun-driver
Date Posted: May-14-2015 at 3:57pm
I also have the GT - 40 P heads and a CR camshaft that may help a little. |
Posted By: mdvalant
Date Posted: May-14-2015 at 4:00pm
that info may have been a little more pertinent earlier in the thread...I'm not sayin just saying.. ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=5009 - '90 Ski (sold) http://www.correctcraftfan.com/diaries/details.asp?ID=5479 - '00 Sport Mississippi River - Bellevue, IA |
Posted By: phatsat67
Date Posted: May-14-2015 at 4:15pm
All you guys with your fancy fuel injected motors.  ------------- |
Posted By: storm34
Date Posted: May-14-2015 at 6:16pm
Just more things to break! ------------- |
Posted By: mdvalant
Date Posted: May-25-2015 at 3:19pm
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Hey guys. Thanks for all the help here. The 95 is NOW running 5000-5100 rpms at 46-47mph on the 1442 acme. Parts replaced: fuel filter, spark plugs, plug wires, cap and rotor. And a few cans of sea foam and some fuel injector cleaner here and there. Culprit: cap/rotor, and plug wires didn't hurt. One plug wire connection on the cap was rusty/dusty and just no good. Was 99% sure when I saw that when replacing that that was our problem. It runs like a beast now! So happy to have it 100%. Thanks again your advice and knowledge sharing.   ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=5009 - '90 Ski (sold) http://www.correctcraftfan.com/diaries/details.asp?ID=5479 - '00 Sport Mississippi River - Bellevue, IA |
Posted By: Bri892001
Date Posted: June-05-2015 at 12:47pm
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Hi Mike, So, it sounds like general tune-up was the final answer? Just curious, so I can add the fix to the http://www.correctcraftfan.com/forum/forum_posts.asp?TID=25584&PN=1&title=poor-mans-gt40-diagnosis" rel="nofollow - GT40 Thread |
Posted By: mdvalant
Date Posted: June-05-2015 at 12:50pm
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Yup, you got it Brian. General tune up did the trick. ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=5009 - '90 Ski (sold) http://www.correctcraftfan.com/diaries/details.asp?ID=5479 - '00 Sport Mississippi River - Bellevue, IA |
Posted By: Bri892001
Date Posted: June-05-2015 at 12:57pm
| Ok cool, thanks Mike. |