1984 sn2001 cuts out at higher RPM? Help! |
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SN2001_1984
Groupie Joined: August-13-2015 Location: Zeeland, MI Status: Offline Points: 56 |
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Posted: August-16-2015 at 2:02pm |
Guys,
Hello....new to the forum as I just picked up my first Ski Nautique. Its a 1984 sn2001 with a 351 with a 1000hrs on it. I test drove it quickly before I bought it but obviously not enough. The engine runs great - starts with a quick turn of the key, idles great and has great power out of the hole. It will run up to 4400 RPM without a problem. AWESOME! However if I go above 2200 RPM for more then 2minutes (trying to pull a tube for instance) it starts to cut out. It bogs down, no backfiring drops a few hundred RPM and then will catch again....if I pull it down to an idle then I can take back off again without problem. Then the issue will reoccur. It seems to be fuel related because the higher the RPM the shorter it last without an issue. So I pulled Fuel/Water separator out and replaced cartridge with a new one. checked the vent tube from gas tank and it's clear. I also have the old mercruiser style fuel pump, the one with the filter on the bottom of it - when I pulled it open there was only a spring in there with 'junk/rust' at the bottom. not sure if someone pulled it or it disintegrated over time??? Anyway I replaced it with a new one. Also the strainer going into the carb was clear of debris. Also the boat has electronic conversion on it so there are no points, cap and rotor look to be in good shape. Any thoughts or where to start. I'm guessing this is still fuel related (pump?/clog on intake tube in gas tank/ or Carb? (has the 4160 holly) OR spark related (maybe coil?) Kid's can't wait to learn to ski ----- Please advise! Thanks for your thoughts in advance...... |
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1984 Ski Nautique 2001 :: 351
Original factory ordered color combo from Silver Spray Sports: Fenton MI |
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SNobsessed
Grand Poobah Joined: October-21-2007 Location: IA Status: Offline Points: 7102 |
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Good to hear your kids want to ski, getting rare these days!
You might want to check the anti-siphon valve for clogs. It is a 90 deg fitting on top of the fuel tank. It's purpose is to prevent gas from filling the bilge in the event of a gas line rupture. It is just a spring check valve. You also might want to get an inline spark tester if you think that the ignition is the problem cause (not my bet). |
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“Beer is proof that God loves us and wants us to be happy.”
Ben Franklin |
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SN2001_1984
Groupie Joined: August-13-2015 Location: Zeeland, MI Status: Offline Points: 56 |
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so yesterday I did take the black hose off of that connector and made sure I could blow through the black hose. Is the checkvalve in the 90degree part attached to the tank? I was able to push a small wire through it? it felt like it was a little stuck at first? not sure I'm in the right area?
thanks for the help. |
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1984 Ski Nautique 2001 :: 351
Original factory ordered color combo from Silver Spray Sports: Fenton MI |
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SNobsessed
Grand Poobah Joined: October-21-2007 Location: IA Status: Offline Points: 7102 |
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Yep, that's it. Have you tried it since you cleaned it?
Another diagnostic approach is to feed the fuel pump from a separate gas can to test. |
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“Beer is proof that God loves us and wants us to be happy.”
Ben Franklin |
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8122pbrainard
Grand Poobah Joined: September-14-2006 Location: Three Lakes Wi. Status: Offline Points: 41040 |
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You bought a boat designed for skiing and you are pulling tubes??? Welcome to CCfan, Dump the tubes. |
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SN2001_1984
Groupie Joined: August-13-2015 Location: Zeeland, MI Status: Offline Points: 56 |
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Thanks SN....I plan to put it in the water in the next couple nights to test again. I"ll report back.
8122 - gotta keep those kids happy - the good thing is that they are excited to learn to ski and wakeboard so its not a total loss :) |
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1984 Ski Nautique 2001 :: 351
Original factory ordered color combo from Silver Spray Sports: Fenton MI |
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8122pbrainard
Grand Poobah Joined: September-14-2006 Location: Three Lakes Wi. Status: Offline Points: 41040 |
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Get the kids out on the water |
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Toertel
Gold Member Joined: August-26-2013 Location: Atlanta Status: Offline Points: 775 |
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had sames symptom in my EFI (so this might not help, but don't know your setup).
Cap and Rotor were shot. new cap, rotor, plug wires, spark plugs and coil and now she runs like a champ again |
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1994 Sport Nautique
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91NaughtyQ
Senior Member Joined: July-27-2015 Location: NC Status: Offline Points: 287 |
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SN20011984 - There are some real pros on here that can help. Take a picture of your engine and post it. I was having the same type symptoms in my 1991 and thought is was fuel. Turned out to be something else once guys on here saw what type of ignition system I had. The knowledge on here is amazing. Welcome to the club.
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SN2001_1984
Groupie Joined: August-13-2015 Location: Zeeland, MI Status: Offline Points: 56 |
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I will post some pics when I get home tonight. For now the motor is a 351 PCM with electronic conversion [rotor and cap look to be in good shape] original coil with the resistor bypass. Not sure how old the conversion kit is, just seems like its fuel since I can almost predict when its going to happen??
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1984 Ski Nautique 2001 :: 351
Original factory ordered color combo from Silver Spray Sports: Fenton MI |
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Toertel
Gold Member Joined: August-26-2013 Location: Atlanta Status: Offline Points: 775 |
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did you take the cap off and look at the contacts?
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1994 Sport Nautique
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SN2001_1984
Groupie Joined: August-13-2015 Location: Zeeland, MI Status: Offline Points: 56 |
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Yes cap and rotor contacts appear to be in good shape.
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1984 Ski Nautique 2001 :: 351
Original factory ordered color combo from Silver Spray Sports: Fenton MI |
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SN2001_1984
Groupie Joined: August-13-2015 Location: Zeeland, MI Status: Offline Points: 56 |
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I'm planning on putting in the water again tonight.....
what things should I be testing while in the water? [its a good 2hours by the time drive to lake/unload/test/load, so i would like to try as much as possible?] I plan to :: 1. test fuel vent [remove gas cap if needed to verify] 2. test coil voltage to distributor to be sure the isn't any voltage drop. I don't have a fuel pressure gauge, but might be a good idea to pick up some flexible fuel line and barb connectors and put a gauge before carb...? any other diagnostic tests I can perform while its in the water that you guys can think of? |
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1984 Ski Nautique 2001 :: 351
Original factory ordered color combo from Silver Spray Sports: Fenton MI |
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GottaSki
Grand Poobah Joined: April-21-2005 Location: NE CT Status: Offline Points: 3338 |
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I don't have the feeling you cleaned the AS valve sufficiently yet. There could also be a cone screen in the dip tube that would clog first. Disassemble the entire dip tube assembly.
A gauge would tell you its loosing fuel. We sort of already know that. To truly conclude diagnostics, one would need to place a vacuum gauge at the gazzinta and a pressure gauge at the gazzouta of the pump. |
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"There is nothing, absolutely nothing, half so much worthwhile as messing around with boats...simply messing."
River Rat to Mole |
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SN2001_1984
Groupie Joined: August-13-2015 Location: Zeeland, MI Status: Offline Points: 56 |
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When I disassembled the AS tube yesterday - I was able to blow the hose out the back of the boat. Then I took a small diameter steel flexible wire and pushed it down the 90degree connector on the tank and felt some resistance and was then able to push it down.
Is there a different procedure to make sure this is clean/free/lubed? Am I correct that is it still happens when running tonight that I can just undo the gas cap quickly [i know be careful of water entering] to test the AS valve system to eliminate that as a variable? oh yeah --- and I did pull the dip tube [fuel feed] assembly out - no screen on the bottom of it and I was able to blow through it as well. |
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1984 Ski Nautique 2001 :: 351
Original factory ordered color combo from Silver Spray Sports: Fenton MI |
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TRBenj
Grand Poobah Joined: June-29-2005 Location: NWCT Status: Offline Points: 21141 |
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You need to take it off and look through it. It's a spring loaded check valve, sticking a wire through it won't tell you if its partially clogged.
No idea where you came up with the gas cap idea. Don't do that. |
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SN2001_1984
Groupie Joined: August-13-2015 Location: Zeeland, MI Status: Offline Points: 56 |
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I thought when i looked at it last night the 90degree piece is aluminum and welded to the tank????
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1984 Ski Nautique 2001 :: 351
Original factory ordered color combo from Silver Spray Sports: Fenton MI |
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SN2001_1984
Groupie Joined: August-13-2015 Location: Zeeland, MI Status: Offline Points: 56 |
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Pics of engine for those interested.......
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1984 Ski Nautique 2001 :: 351
Original factory ordered color combo from Silver Spray Sports: Fenton MI |
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SN2001_1984
Groupie Joined: August-13-2015 Location: Zeeland, MI Status: Offline Points: 56 |
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TRbenj -- I may be confused....is the check valve assembly inside the 'vent tube pickup' on the drivers side of the tank. OR is it in the 'fuel pickup' in the center of the tank??
thanks for your help! |
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1984 Ski Nautique 2001 :: 351
Original factory ordered color combo from Silver Spray Sports: Fenton MI |
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91NaughtyQ
Senior Member Joined: July-27-2015 Location: NC Status: Offline Points: 287 |
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SN2001_1984 - The anti siphon valve is in the fuel pick up in the center of the tank. It should be hooked to the end of your fuel line.
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SN2001_1984
Groupie Joined: August-13-2015 Location: Zeeland, MI Status: Offline Points: 56 |
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perfect, thanks for the clarification 91naughtyQ - I do need to disassemble that completely tonight and check to make sure its clear.
thank you! |
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1984 Ski Nautique 2001 :: 351
Original factory ordered color combo from Silver Spray Sports: Fenton MI |
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Gary S
Grand Poobah Joined: November-30-2006 Location: Illinois Status: Offline Points: 14096 |
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Here is a pic of an aluminium one on some type of boat,it's what the hose is connecte to.
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91NaughtyQ
Senior Member Joined: July-27-2015 Location: NC Status: Offline Points: 287 |
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Not really. If it is like most you can unscrew it from the 90 degree elbow and check it. I just did this when I was troubleshooting my problem. Once you get to it, it should be springy and move freely. If it is jammed up you will know it.
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91NaughtyQ
Senior Member Joined: July-27-2015 Location: NC Status: Offline Points: 287 |
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Sorry I misread your post. Yeah take a look at it for sure. I thought you were asking if you needed to disassemble it.
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SN2001_1984
Groupie Joined: August-13-2015 Location: Zeeland, MI Status: Offline Points: 56 |
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So, Apparently there is not AS valve on my set up.
Removed fuel feed tube and 90 degree elbow and there is no valve in it at all??? Guess that variable is ruled out :) Fuel feed tube assembly :: Vent tube:: taking it out tongiht but not even sure what to do next.....????? Any ideas? Could it be fuel pump? What are the votes fuel vs electronic? |
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1984 Ski Nautique 2001 :: 351
Original factory ordered color combo from Silver Spray Sports: Fenton MI |
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8122pbrainard
Grand Poobah Joined: September-14-2006 Location: Three Lakes Wi. Status: Offline Points: 41040 |
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Denny,
Don't rule out an ignition problem. You mentioned the engine has a EI conversion in the distributor. Some brands are known problems although they typically quite all together. For the fuel pump, you can "T" in a pressure gauge to check it. |
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SN2001_1984
Groupie Joined: August-13-2015 Location: Zeeland, MI Status: Offline Points: 56 |
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Ok, out on water and back .....the wife drove while I observed. I have only 6.8v coming from coil at idle. When at 3000 rpm I have 9.5volts. Seems odd to me. Also I'm pretty sure secondaries on carb are not opening at all....looks like a carb rebuild as they only opened if I opened them mannually.
Thoughts? ??? |
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1984 Ski Nautique 2001 :: 351
Original factory ordered color combo from Silver Spray Sports: Fenton MI |
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backfoot100
Platinum Member Joined: January-03-2007 Location: United States Status: Offline Points: 1897 |
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Secondaries won't open until the engine demands call for it at speed and underway. 3K RPM definitely won't open them.
They're designed to not open until somewhere around 40MPH or WOT. Whichever comes first. |
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When people run down to the lake to see what's making that noise, you've succeeded.
Eddie |
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SN2001_1984
Groupie Joined: August-13-2015 Location: Zeeland, MI Status: Offline Points: 56 |
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Ok thanks backfoot100.
What about the coil readings....anyone with advise on those? " I have only 6.8v coming from coil at idle. When at 3000 rpm I have 9.5volts. Seems odd to me" at this point - it seems like a coil or fuel pump??? |
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1984 Ski Nautique 2001 :: 351
Original factory ordered color combo from Silver Spray Sports: Fenton MI |
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SNobsessed
Grand Poobah Joined: October-21-2007 Location: IA Status: Offline Points: 7102 |
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Check coil V at + side of coil. If you have resistor bypassed it should read same V as alternator output, or close to it..
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“Beer is proof that God loves us and wants us to be happy.”
Ben Franklin |
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