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View Full Version : Dealer cannot figure out Stalling problem


woodskier
08-02-2007, 12:54 PM
I am desperate. I totaly refurbished my 84 S&S, 351, and had the carb rebuilt at the dealer. The boat was in the water a total of two days, The carb rebuild was screwed up, the secondaries were not kicking in, etc. Back to the dealer, and they have been working on it all week. It runs great in the shop, and during water testing runs great for a short period,then stalls at high RPM. They have


Checked and adjusted the carb to get the secondaries running
Found a fuel filter they put in backwards
Replace dist cap/plugs/wires/condenser/points ( which had already been done)
Adjusted the timing
Replaced the fuel pump
Replaced the check valve and checked gas tank/ fuel lines again
Hooked up 5 gallon gas can directly to fuel pump
and I am sure everything else they can think of.

I reccomended checking the springs and weights under the distributer plate, and they are doing that now.

ANY OTHER IDEAS

It only now stalls at high RPM under load- I want my boat back

Thanks in advance

JimN
08-02-2007, 01:34 PM
It's not the recommended method but have they run it without the flame arrestor? At high speed, if it does fire through the intake, the flame will be blown backward, but someone could use an inspection mirror to make sure the carb is supplying fuel properly.

I don't suppose they have another carb to test with, do they?

kdtechnologyinc
08-02-2007, 01:49 PM
Replace the coil.

woodskier
08-02-2007, 01:50 PM
They seemed convinced the carb is working properly, and are replacing the fuel tube from the pump to the carb. Switching out carbs sounds like a great idea to me. I am not convinced they did'nt screw up the carb when rebuilding. I will check if they have one.

woodskier
08-02-2007, 01:54 PM
Excuse my ignorance- How does that effect the preformance only at high RPM's when the boat is in the water under laod) vs the shop?

JimN
08-02-2007, 02:11 PM
Testing on a trailer is OK for finding out if the timing is close, water pump, compression tests and some other things but the only real test is on the water. The engine's load is what determines what it's capable of. There's no significant information about power or torque that can be gained without a load. The fuel/air demands of the motor are different under load, too.

kdtechnologyinc
08-02-2007, 02:17 PM
Had a '85 S&S that would only sputter at high RPM like when crossing a recreational lake, but would run fine at slower speeds (30~36 MPH) in the slalom course. The more RPM's you turn, the more times your plugs fire in a given time. It gets to the point where you don't have enough volts to light off the air/fuel mix. We swapped coils with another '85 S&S and that cured the problem. Had the exact same thing happen a few years later in my '88 IROC when it was 5 years old. It would kick down out of overdrive on the highway and the RPM's would flutter.

This may not cure the problem you're having, but ignition coils are cheap and they do fail.

woodskier
08-06-2007, 11:23 AM
Thanks Jim and KD, The dealer is on a lake, and it was tested numerous times on the water. They finally called and said it was fixed. I tested it myself for 20 minutes on water. Except for it stalling out once ( which we determined it was out of fuel), the boat ran better then ever at all RPM's. In addition to the above they had replace all the fuel lines. When I asked them what had caused the problem, they said it was a combination of all the above.

$675 later, ( now almost $1200 includeing the original carb rebuild) I got it home Friday afternoon , and put it on my lake, and again it ran great Friday. Saturday my wife pulled skiers and tubes all day while I was away on business. I got home Sunday dying to get on the water for my first ski of the YEAR, and it would'nt start unless I sprayed starter fluid in the carb, once started it was fine at 1K,1.5K,2K RPM. At 2.5K RPM it started to sputter a little, at 3-3.5K RPM it would stall sometimes immediatly, some times after a few minutes at that speed.

Again , I am bringing it back to them this afternoon, and I will have them replace the coil. ( Maybe I should just do my myself and save the hassel of getting the boat out of the water plus the 40 minute trip) Anything else you guys can think of? Could a crack in the block or heads etc cause something like this at high RPM's. There was a some water in the oil when I changed it after the winter layover, but no foaming or anything like that now. I am thinking the worse here, but after all this I am getting very frustrated, not to mention broke. Fortunatly the new upholstery and carpet job looks unbelievable, I will post some pictures if I ever have the boat long enough to take them.

Thanks again in advance. This forum is a fantastic wealth if info.

JimN
08-06-2007, 12:27 PM
Use gas, not starting fluid.

Did they do a compression, vacuum or cylinder leakdown test? If it runs rough at high RPM, I would consider it. In light of the water getting into the oil, it's possible that you have a bad head or intake manifold gasket. The three tests I mentioned will verify this.

woodskier
08-06-2007, 02:07 PM
Thanks Jim,

Do I do this before we replace the coil and see if that is the issue? If possible I would like to avoid having to take the boat off the lake again, especially since I still have that stupid bar on the trailer ( next project) and I am not sure I will be able to drive the boat at enough RPM's to get it up the steep ramp to set the bar in the bow eye.

Dan K
08-06-2007, 02:16 PM
Thanks Jim,

Do I do this before we replace the coil and see if that is the issue? If possible I would like to avoid having to take the boat off the lake again, especially since I still have that stupid bar on the trailer ( next project) and I am not sure I will be able to drive the boat at enough RPM's to get it up the steep ramp to set the bar in the bow eye.
This is called powerloading, be careful about doing this at your ramp, powerloading washes out the ramp and makes it even steeper. Most ramps I have ever been to do not allow this.

wesgardner
08-06-2007, 04:16 PM
Hey Woodskier,

How 'bout one of these - eliminates points, ballast resistor and remote coil...high capacity - open up your plug gap for better burn...beautifully machined and wit ha set of their wires - you get SPARK..oh yeah, you can advance your timing a bit as well...

http://www.performancedistributors.com/marinedui.htm

Wes

JimN
08-06-2007, 05:09 PM
woodskier- back the trailer a little deeper into the water, crank the winch till the bow roller makes contact and when it's out of the water, put your back against the hull and lift with your legs. It's a bad design but it's possible to beat it.

I would do the tests before the coil- if you find a problem, it'll probably eliminate the coil as a suspect. The motor needs to be warmed to normal operating temperature to do them but it will cool down somewhat during, so don't worry if it's not burning hot. The compression test- pull all of the spark plugs, insert the gauge and crank it for a few revolutions (4-5). Make sure to watch the first "pop" of the gauge. Higher is better. Write the compression down for each cylinder. You want to see about 150psi within about 10% for all of them. If you have any two adjacent cylinders with low numbers, you have a bad gasket, usually due to an overheat.

woodskier
08-06-2007, 05:10 PM
Looks cool but expensive at this point. I called the dealer and he said they switched out the coil and it did not help. Assuming this was done after other issues were fixed, I assume this will not be the root cause. So lets recap the Tried, Replaced,Adjusted by dealer list:

Rebuilt Carb
Flushed fuel lines
Installed Fuel/Water seperator
Checked and adjusted the carb to get the secondaries running
Reversed a gasket to the accelerator pump which was installed backwards
Replaced fuel filter
Replace dist cap/plugs/wires/condenser/points ( which had already been done)
Checked springs/weights under Dist plate
Adjusted the timing- off 6 drgrees
Replaced the check valve and checked gas tank/ fuel lines again
Hooked up 5 gallon gas can directly to fuel pump
Checked throttle cables at both ends
Switched out Coil
Replaced all fuel lines, eliminated in-line glass filter
Replaced Fuel pump with one with built in filter

What am I missing- Will hopefully get the boat to them tomorrow so they can do the compression, leakage, vacume tests

JimN
08-06-2007, 05:10 PM
DanK- you're not talking about the old public launch at Lauderdale Lakes, are you?

drucrew
08-16-2007, 11:20 PM
have you replaced the coil

sbuell
09-13-2007, 02:09 PM
Woodskier,

Pushing this back to the top and curious if you ever came up with a solution. Sounds very similar to the issue I have had all summer. Basically been through the same list of checks but I have changed the coil. TWICE! I can run fine with the kids skiing or wakeboarding, basically anything less than about 22 mph. If I push above that it starts coughing and will stall if I keep it there.

Hope you found the magic cure.

JimN
09-13-2007, 03:20 PM
sbuell-
OK, so changing the coil didn't fix it, so you changed it again and it still didn't do it. How old are your plug wires, and this includes the coil wire? How old are the plugs? Have you actually measured the fuel pressure, or just pressed the Shrader valve? Pressing the valve only tells you that you have some fuel pressure, not if it's adequate. You need to do the diagnostics the right way, not just replace parts that seem to be bad. How old are the cap and rotor? Have you looked here for other threads for the same issues and tried everything listed? Before you replace anything else that might still be good, look through the threads. It'll probably save you some money and get the boat running faster.

KHall
09-13-2007, 03:49 PM
The motor def needs the all pressure tests JimN has mentioned. Compression & fuel. I would still keep that carb in mind as a potential problem despite the "rebuild".

JimN
09-13-2007, 06:38 PM
I'm sorry, I forgot it has a carb. Was that checked/replaced? I would make sure the diaphragm is good and not leaking, although now that I'm typing this, it feels like déjà vu. Was the coil wire replaced? For some reason, I have seen many bad ones in new wire sets. If you can, get a spark intensity checker. Better yet, if you know of an auto service shop that works on older cars, have them hook it up to the Sun machine.

If it's lumpy above 2200 and there's no power, the compression test may reveal that you have problems. OTOH, anything can be repaired.

sbuell
09-14-2007, 12:16 AM
Jim,

Quick run down of everything that has been done thus far.
Install electronic ingition conversion
Tear down and clean the carb
Adjust carb floats and choke setting
New plug wire, plug, cab, rotor, coil, main ground wire, all wiring from ignition switch to coil.
New fuel filter and hoses.
Checked and cleaned all fuel filters.
Timing
Checked dist weights and springs.
Checked secondaries but stalling is well before they should kick in.
Tried with and without the flame arrestor.

I admit that I have not done a vaccum test or a compression test and that is where we go next.

Thanks

JimN
09-14-2007, 12:37 AM
If you can have a cylinder leakdown test done, that's good, too.

Have you wiggled the wires at the ignition switch and safety switch? What about on the circuit breaker at the rear of the motor?

Tim2ski
09-26-2007, 12:20 PM
I have been watching this thread very closely. My 89 PS190 has a very similar problem. My problem also started when I was having some starting issues and took my Holley 4160 in for a rebuild. When we got it back I was still almost exclusively wakeboarding so we never took the tach above about 22k on takeoff. At the end of the season I started slalom skiing and the engine would start stalling out of the hole. The problem is not possible to duplicate out of the water, so it took awhile to get my mechanic out of the shop and out onto the water. He made some adjustments to the mixture and seemed to help, but not eliminate the problem.
We have dealt with the problem all season, but have recently started skiing on a course and there is NO room for a stall. I have to have time to fix my wakeboard shorts before I hit the gate:-) We even went as far as to replace the carb with a new 4160 while we were on the water. This did not work. Mine will start out running nicely at first but degrades quickly and continues to get worse.
I have not been as far through the system as Woodskier. I was wondering, with all of the good tips that have been posted, should I start with electrical or fuel?
Same issues or should I start a new thread?
I will be watching...

JimN
09-26-2007, 12:58 PM
Start with the basics- fuel quality and flow from the tank are the first things I would check after finding out how the mechanic set the carb up in the first place. Just going all in with the idle screw(s) opening it 3/4 turns and using the old jets won't guarantee correct fuel delivery. Fuel issues are always high on the list of culprits when a motor runs bad. Next, or first, if you want, are compression and vacuum. If the compression and vacuum are good, move to spark timing, dwell and intensity. If it has electronic ignition, don't automatically assume it's always going to be perfect. Watch for stable timing indication. If it jumps around, it could be bad distributor bushings, sticky weights/springs or something like those. If spark and compression/vacuum are good, the only thing you need for it to run properly is the correct amount of fuel being delivered, at the right time.

The quickest way to find out what the problem would be to add some fuel while it's bogging. Squirt some gas in through the flame arrestor using something like a mustard bottle. If it backfires, it'll be safer than removing the arrestor. If it runs better, you'll know that it needs more fuel in that RPM range. Make sure you have your safety gear handy, just in case.

What is the condition of your cap/rotor, plugs/plug wires and PCV valve? Fuel filter is how old? Have you ever checked the quality of the gas in your tank?

sbuell
10-15-2007, 02:35 PM
Okay, sort of a delay in getting back to this issue. I have done a compression test now. I put it off not really wanting the results that would say "spend big $$". As it turns out everything came out pretty good. All eight cylinders checked out within 10% of each other dry and wet. All pretty well clustered around 140 psi. All consistently pumped up at the same sort of rate and all hit the same mark on the second test each time. Definitely no smoking gun here. This means I am back to scratching my head for answers.

woodskier
10-15-2007, 04:49 PM
Sorry, Have lost track of this thread since I started it, but seem to have worked thru the issue. Not exactly sure if your problem was exactly the same as mine, but two things seem to have eliminated the problem of stalling at high RPM, and not getting gas after sitting for a few hours.

First, on a test ride with a new mechanic, I still was stalling out at high RPM, or when simulating a medium throttle advance from neutral like pulling a child up skiing. The mechanic noticed the linkage to the accelerater pump was loose, and not kicking in quick enough. After adjusting the linkage we saw a huge difference.

Second, I was convinced that the recently installed water fuel filter was limiting the amount of gas getting to the fuel pump. They had installed it on the opposite side of the boat which created an additional 6 feet of hose. When I removed the water/fuel seperator from the equation, I have not had an issue since.

Hope this helps, PS I was OOTC when you called me back. Sorry I missed you.