Timing Puzzle |
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79nautique
Grand Poobah Joined: January-27-2004 Location: United States Status: Offline Points: 7872 |
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any auto parts house
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jefmar
Newbie Joined: October-30-2005 Location: United States Status: Offline Points: 32 |
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Yes. It has new electronic ignition conversion (GLM Part number 72540) in the original Prestolite distributor. Where do you purchase distributor springs?
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1989
Ski Nautique 2001 |
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79nautique
Grand Poobah Joined: January-27-2004 Location: United States Status: Offline Points: 7872 |
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I would clean and lube the plate and change the springs to correct the problem with the advance. Your springs seem to be to stiff and not allowing enough advance. It's an electronic ign already and not a points dist correct?
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jefmar
Newbie Joined: October-30-2005 Location: United States Status: Offline Points: 32 |
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Thank you for the input
64 skier - I took it apart a couple weeks ago.. the springs are functional. 79 - the mechanical advance inside the distributor seems to move okay; however, there is very light corrosion on the metal parts.. Do you think it is worth the effort to disassemble and lubricate the mechanical advance or would you buy a new distributor? |
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1989
Ski Nautique 2001 |
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79nautique
Grand Poobah Joined: January-27-2004 Location: United States Status: Offline Points: 7872 |
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It sounds like you are referancing where the wire is on the cap relative to the diagram in the manual and if so don't it's meaningless. All you have to worry about is the order and not location.
You need to check and make sure that the base plate for the mechancal advance is moving freely and not gumed up before you start changing the advance springs to get a little more top end advance on the timing. |
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64 Skier
Senior Member Joined: February-08-2004 Location: United States Status: Offline Points: 415 |
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You got me stumped on the wiring. I'd have to see an engine in front of me to understand.
However, you should have 10 more degrees of advance. The new electronic ignition in the old Distributor is OK, but it sounds like the advance is not working properly. Take it apart and look at the springs. |
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jefmar
Newbie Joined: October-30-2005 Location: United States Status: Offline Points: 32 |
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Sorry for the slow troubleshooting. Finally had a chance this weekend..
I checked the spark plug wiring, reset the timing to around 10 btc at idle, adjust idle mixture and idle screws, and noted the following timing curve: 600 RPM – 10 degrees 1000RPM – 10 1500RPM – 12 2000RPM – 18 2500RPM – 20 3000RPM – 22 What do you think? I also noticed that spark plug wiring order is correct for LH rotation but based on the schematic in the repair manual the wires appeared rotated clockwise one position (i.e.; the front is no. 6 rather than no. 2). Does this mean anything? |
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1989
Ski Nautique 2001 |
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jefmar
Newbie Joined: October-30-2005 Location: United States Status: Offline Points: 32 |
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79.. Thanks for the tip.
Thanks Jeff. I forgot to mention that I have a new PCV valve. It was changed when I fixed the vacuum leak. The new one seems to function correctly. |
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1989
Ski Nautique 2001 |
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JEFF KOSTIS
Gold Member Joined: April-19-2005 Location: United States Status: Offline Points: 817 |
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All are possibilities. If timing is OK, check the PCV valve. It may be sticking and causing a leak and unstable idle. If you put your finger over the end of the PCV valve at idle, you should hear it "click" and suck your finger in. When you pull off your finger, it should "click" again.
Jeff... |
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79nautique
Grand Poobah Joined: January-27-2004 Location: United States Status: Offline Points: 7872 |
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Be sure that the idle is at around 600-800 rpm before you set the timing, or you will get false reading because you will start to engauge the mechanical advance.
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jefmar
Newbie Joined: October-30-2005 Location: United States Status: Offline Points: 32 |
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Thank you for the input
Jeff, Rick & 79 - I will check the spark plug wiring, reset the timing to around 10 btc at idle, adjust idle mixture and idle screws using the vacuum gage, and note the timing curve... later this week. 64 skier - there is no knock when the timing is set at 10 or 18 btc at idle. The rough, high idle was mostly caused by a vacuum leak in the hose to the pcv valve.. a tune up helped too. |
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1989
Ski Nautique 2001 |
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882001
Senior Member Joined: October-21-2003 Location: United States Status: Offline Points: 332 |
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^^^^ well said 79^^^^
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kemah texas
1988 skinautique "2001" |
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79nautique
Grand Poobah Joined: January-27-2004 Location: United States Status: Offline Points: 7872 |
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Remember you have to set the timing first then adjust the carb's idle and idle mixture screws and not the other way around. Get the timing at 8-12 btc then adjust the idle, then fine tune the carb using the vacumm gauge to adjust the idle mixture screws and idle screw.
Make sure that the wires aren't crossed like rick suggested as well. Set the base timing then see what it is at 3000rpm and that will tell what the full advance is. |
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64 Skier
Senior Member Joined: February-08-2004 Location: United States Status: Offline Points: 415 |
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Couple of questions? Does she knock with that much retardation? Initial timing is "recommended" at 10-12 degrees but the only way to time the engine is in the boat running and listening to the engine as you further retard. This is also the only way to get full power. For some reason I hvae 3 timing lights...they all read different but within about 2 degrees.
Before you time her on the lake...measure full advance and make a simple plot of timing versus rpm up to 3000 RPM. Springs get old and I've seen some "jump" which causes a stumble simlar to a carb with a weak accelerator pump. Time the engine with the fuel you plan on running. The gas we purchase on the lake is somewhat less quality than what I buy at the pump. This also made a difference in my boat. When I was tuning I had a fresh tank of premium. When pulling skiers in the spring she'll have an old tank with "Stabil" so I save the timing check for later. What cured the rough high idle? |
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Rick
Senior Member Joined: March-03-2004 Location: United States Status: Offline Points: 338 |
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This is a long shot but make sure 2 spark plug wires aren't crossed.check that the firing order is correct. If 2 of the wires are wrong you get a rough idle hard start and depending on the order advancing the timing can make it better.
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JEFF KOSTIS
Gold Member Joined: April-19-2005 Location: United States Status: Offline Points: 817 |
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I would try it at different rpms and take note of it so you can see a rough curve. Im not sure on the exact degrees for the rpm, and I forgot, you might have trouble with a generic timing light as the markings on the engine usually dont go that high. You can get a rough idea to see if it advances at all.
Jeff.. |
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jefmar
Newbie Joined: October-30-2005 Location: United States Status: Offline Points: 32 |
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Thanks Jeff. You are right, I advanced rather than retarded the timing. I wish I would have thought of checking the mechanical advance when I had it in the water earlier today. I will check it later this week.. It looks like I should be at about 32 degrees btc at 3000RPM from other posts... does that sound right?
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1989
Ski Nautique 2001 |
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JEFF KOSTIS
Gold Member Joined: April-19-2005 Location: United States Status: Offline Points: 817 |
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If you had to set the timing to 18 btc, then you are advancing it. Did you try putting the timing light on it and start at idle and increase rpm as see what it is?? This will either prove correct or incorrect advance.
Jeff... |
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jefmar
Newbie Joined: October-30-2005 Location: United States Status: Offline Points: 32 |
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I recently bought my '89 Nautique with PCM/Ford 351. It has low hours - 380 hrs - the previous owner was adamant that the hours are original. It was running rough with a high idle when I bought it.. but that is fixed now. I have one remaining problem – when the timing is set per specifications (10 degrees btc) it stumbles/coughs under heavy acceleration in the water. I played with the timing by trial and error with the boat in the water and found that if the timing is retarded to 18 degrees btc it does not stumble; however, at 18 degrees btc the starter is slow to crank the engine. The starter cranks the engine normally at 10 degrees btc. I have a new carb and no vacuum leaks and noticed that the idle is not totally consistent (it varies from 600-800RPM) between heavy acceleration attempts. I am guessing that something is causing my timing to change. Or the distributor is not advancing correctly under power. But, the spring mechanism inside the distributor seems to move okay and the springs are functional. I also guessed that my timing chain/sprockets are loose/sloppy. Or the distributer is not set correctly...
The boat is running well but I do not feel comfortable advancing the timing so far that it affects how quickly the starter cranks the engine. Here is my diagnostic results and what I have changed so far: -Fuel pressure: 4 psi -Fuel flow: did not measure it carefully but half filled a soda can with about 10 revolutions of the engine. -Vacuum: Steady 19"Hg at idle. I had some leaks but fixed them. -Compression: looks great (120-135 psi) -New Holley 4160 marine carb for 351 (Holley part number HLY-0-80319-1) -Cleaned spark arrestor -New electronic ignition conversion (GLM Part number 72540) in the original Prestolite distributor -New distributor cap, rotor, spark plugs, spark plug wires -New coil -New gas filter/oil water separator -New PCV valve Before I tear into the timing chain or buy a new distributor, does anyone have a suggestion of what the problem is?? What would you try first?? |
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1989
Ski Nautique 2001 |
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