Idle problem & hesitation when warm
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=30783
Printed Date: October-08-2024 at 11:18pm
Topic: Idle problem & hesitation when warm
Posted By: Grey Hair Kid
Subject: Idle problem & hesitation when warm
Date Posted: July-16-2013 at 3:47pm
Hello New guy here,
I have learned a ton about my 1984 Ski Nautique by lurking for the past week. I have read several carb threds and have tried a lot of the recommended fixes, but I still have a hesitation and sputtering when I am initially accelerating once the boat is warmed up. Initially the primary was wet and gassy, so Sunday I rebuilt the primary of my Holly 4160 replacing the power valve. float needle and seat, gaskets, diaphragm. I adjusted the float level and took the boat out yesterday. Voila! no gassy wet primary anymore. BUT after it warmed up it idled like crap and hesitated out of the hole. I played around a little with the two air screws on the metering block and screwing them in (clockwise) 1/2 turn made the problem slightly better. I haven't looked up the proper way to adjust those screws, so if anyone can direct me to that information, I'd be obliged.
Any suggestions where to go from here?
Oh my carb rebulid kit didn't have the O rings for that little tube that extends out from above the power valve. I felt tight and the rings looked okay, so I left it as is.
Any help from you guys would be greatly appreciated.
GHK
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Replies:
Posted By: Grey Hair Kid
Date Posted: July-16-2013 at 3:49pm
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I forgot to mention that this problem existed Before I messed with the carb.
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Posted By: Grey Hair Kid
Date Posted: July-16-2013 at 4:07pm
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I thought of another non issue. The boat has EI and there is no ballast resistor on the boat. I also replaced the coil for good measure. Another question while I'm at it. I was going to replace my 7mm PCM wires with new ones. while at the dealer picking up the wire kit I ordered, I talked to the mechanic and he sai the wires on the newer boat have up to 1,000 Ohms of resistance. This got me curious and we measured my coil wire at 0.6 Ohms. The new replacement wire had 388 Ohms of resistance. This concerned me, I didn't want to reduce spark, so I didn't take the new wires. TH dealer called PCM and they advised that those are the only wires they have for a 1984 Ski Nautique. Should I go aftermarket, or am I worried about nothing.
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Posted By: backfoot100
Date Posted: July-16-2013 at 4:52pm
David,
The idle mixture screws are set together with the timing and idle RPM.
First make sure the accelerator pump arm is adjusted so there is no slop in the arm. Moving the accelerator linkage the smallest amount should get you a pump shot out of the pump nozzles in the primary throat of the carb.
Make sure the timing is set properly 8-10 BTDC warmed and idling. Then set the idle mixture screws. Turn each one in until they gently bottom out. Then back them up about 1 and 1/2 turns. That's a good starting point.
Put the boat in the water and get it warmed up. Put it in gear, idling. Then turn turn each screw in one at a time until the the engine stumbles, then back it out to the highest engine RPM. Do the same on the other screw. You may have to reset the idle RPM screw to maintain 600-650 idle RPM (650 in neutral, 600 in gear). You will probably have to go back and forth making the adjustmennts until everything is dialed in.
If everything is set right, your stumble should go away.
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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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Posted By: SNobsessed
Date Posted: July-16-2013 at 4:58pm
David - Welcome to the site. I will try to answer best I can.
The carb issues sounds like the idle passages are still cogged up (common problem).
You may have you take it apart again & soak it more - use small wire to clean out the passages.
No ballast resistor is OK if coil is not getting too hot, you should be able to touch it without going to the ER.
Do you think the plug wires are bad? Maybe pull them with engine running, 1 at a time, to see if they are all firing.
I got a set from NAPA for vintage F150 truck (I had to shorten a few) & they work great, FYI if you want to take away any doubt.
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“Beer is proof that God loves us and wants us to be happy.”
Ben Franklin
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Posted By: Grey Hair Kid
Date Posted: July-16-2013 at 6:14pm
Thanks for the advice guys. I just sprayed the metering block with carb cleaner and blew it out with compressed air, so maybe that wasn't good enough. I also didn't remove those idle mixture screws and clean out those ports. So that is on the list as well as checking the timing (i'll look up how to do that).
Someone at the barber shop (where trustworthy advice is dispensed) has an 86 Nautique and he said to check for broken centrifugal advance springs in the distributor. Do I even have a mechanical advance with EI? I'm such a primate in so many ways.
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Posted By: SNobsessed
Date Posted: July-16-2013 at 6:35pm
Yes, you have a centrifugal advance. If you take the dizzy cap off you should be able to see the springs & weights. If not, take off the plate that hold the sensor..
Your barber was spot on - that could be an issue.
One spring is supposed to be a little loose. Check that the weights move freely.
When you check timing, rev it up to about 3K RPM, The timing should keep advancing until about then.
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“Beer is proof that God loves us and wants us to be happy.”
Ben Franklin
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