Stalling Inboard Motor

Red Monster

Red Monster

Well-Known Member
I emailed Pertronix this message today concerning their electronic ignition I had installed to replace the old points in my distributor. Maybe some clever person here may have a suggestion to make? Thanks, I'm running out of ideas short of putting points back in.

I've spent the last two months trying to figure out why my boat's inboard motor keeps stalling, which began shortly after installing your electronic ignition. New gas, cleaned gas tank, rebuilt carb, new Pertonix coil, new fuel filters, but it still stalls under load. Cruised today for almost two hours off and on over flat calm water, but at the end of the day when I pushed up the rpm past 3000, the motor seemed to lug and then it died. This has happened dozens of times in the past two months while I try to fix the problem. The marine mechanic who installed it is no help: he doesn't know how to test the Pertonix Ignitor he installed, which seems to be overheating and shutting down under load (not at low rpm). When the motor sits for 10 to 20 minutes and cools off, it starts right up and then may or may not rev up 3000 rpm again. The motor is a 1987 Volvo Penta AQ231a so there are no fancy sensors to not work, and the fuel pump is mechanical. Can the Pertronix Ignitor be tested? How? This is getting very expensive and time consuming and frustrating. What good is the Pertronix warranty if I can't get the mechanic who installed it to do anything given the way the stalling seems to happen only after the motor is pushed/loaded for at least 20 minutes?
 
Red Monster said:
I emailed Pertronix this message today concerning their electronic ignition I had installed to replace the old points in my distributor. Maybe some clever person here may have a suggestion to make? Thanks, I'm running out of ideas short of putting points back in.

I've spent the last two months trying to figure out why my boat's inboard motor keeps stalling, which began shortly after installing your electronic ignition. New gas, cleaned gas tank, rebuilt carb, new Pertonix coil, new fuel filters, but it still stalls under load. Cruised today for almost two hours off and on over flat calm water, but at the end of the day when I pushed up the rpm past 3000, the motor seemed to lug and then it died. This has happened dozens of times in the past two months while I try to fix the problem. The marine mechanic who installed it is no help: he doesn't know how to test the Pertonix Ignitor he installed, which seems to be overheating and shutting down under load (not at low rpm). When the motor sits for 10 to 20 minutes and cools off, it starts right up and then may or may not rev up 3000 rpm again. The motor is a 1987 Volvo Penta AQ231a so there are no fancy sensors to not work, and the fuel pump is mechanical. Can the Pertronix Ignitor be tested? How? This is getting very expensive and time consuming and frustrating. What good is the Pertronix warranty if I can't get the mechanic who installed it to do anything given the way the stalling seems to happen only after the motor is pushed/loaded for at least 20 minutes?
Click to expand...
I have experienced this problem with many different boats but especially those that have Mallory distributors. The engines will always start and run well when cold but would lose power when hot would stall and then were impossible to start.
Are these the symptoms you are experiencing?
 
sounds like you need to find a different mechanic, anyway past experience with any electronic ignition that will restart after it cools down is the brain ie ignitor or module. most cannot be tested unless its in a no start mode, you will have no spark in this case, pull a plug wire and check for spark yourself if you can, might save you some time GOOD LUCK
 
you could put the points back in a see if the problem goes away. the problem almost sounds like you have 12 volts running to the coil in run instead of 6-7 volts it should have. i am in Abbotsford and can easily check this for you
 
the problem almost sounds like you have 12 volts running to the coil in run instead of 6-7 volts it should have. i am in Abbotsford and can easily check this for you
 
Yes, Millertime, it runs like a top when it's cold. When the water is flat calm I can even cruise if I don't bumb up the rpm. It takes about 20 minutes to die if I'm cruising in waves. No issues at low rpm, and the motor will alway start if I let it sit for a while. Once it gets hot, it dies cruising in wave. So the problem seems to be when the motor is under load, the Pertronix ingnition overheats and shuts down.

The distributor is the original one with the points removed and the Pertronix electornics installed.

The mechanic says he doesn't know how to test it because it only happens on the water, not when the boat is on the trailer in the shop. Sure doesn't help me a lot.
 
Have you ruled out the tank vapor locking? When it stalls and you cant start it, thats when you need to pull a plug lead and check for spark. It is quite possible that your tank is not venting.
 
Also could be a symptom of a bad coil.
The install of the pertronix could just be coincedental.
 
I just replaced the coil.

I spent two days replacing the vent hose with an expensive flex hose (has wire in it) that bends and will not collapse.
 
Sounds more like a fuel issue with the symptoms you describe. There was an important question asked earlier in this thread and i didn't see an answer. Does it surge and sputter when it acts up or just cut out like you turned off the key?
 
I know our farm tractor motors when a plugged fuel or fuel issues will be fine in the shop or low rpm but put under load then it slowly dies
 
It could be a fuel pump developing vapour lock too if it is located near something hot and the ventilation is poor.
 
check the ballast resistor for your coil and see if it is still attached, on some engine they used a resistance wire. Maybe the mechanic took it out???? I have used pertronix before and they are way better than points.
 
Regarding the way it stalls, it seems to just hesitate and cut out without surging.

Yesterday (as well as the last time I tested it) I cruised at 2800 to 3000 rpm without issue on flat calm water. It ran flawlessly. In the past it stalled after about twenty minutes doing the same thing if the boat were pushing through waves. Then I bumped up the rpm and it start to hesitate a bit, and when I pulled back on the throttle the motor died and would not start until the motor sat for about 15 minutes. Then it started right up again.

It never stalls at low rpm. On many occasions I've returned to the ramp running the boat at 7 mph because once it started stalling it would not run at above low rpm.

Pertronix has replied and suggested I send them the ignition for testing.
 
I know most mechanics will go along for a ride if it is the only way to diagnose a problem. Find one who will bring along testing equipment and get the engine to act up while they are there to pin it down. Otherwise your chasing a ghost.
 
It just occured to me that the plumping of the kicker's fuel line could be the issue. I plumbed the kicker off the fuel filter that is also supplying the main inboard motor. Maybe the inboard motor is sucking air through the kicker line because of a leaking check valve in the primer bulb? I guess I could install an inline anti-siphon valve or on/off valve. Or I could just disconnect the fuel line from the kicker assuming the valve at the disconnect stops air from entering?
 
Red Monster said:
It just occured to me that the plumping of the kicker's fuel line could be the issue. I plumbed the kicker off the fuel filter that is also supplying the main inboard motor. Maybe the inboard motor is sucking air through the kicker line because of a leaking check valve in the primer bulb? I guess I could install an inline anti-siphon valve or on/off valve. Or I could just disconnect the fuel line from the kicker assuming the valve at the disconnect stops air from entering?
Click to expand...
just pinch off the line, and run it, use some needle nose vise grips if you have, you only need enough pressure on the vise grips to collapse the rubber hose don't over tighten or you'll damage the hose.
I would bet it is either the ignitor or the pick-up coil, I worked for Toyota for years and seen many, many ignitor issues including recalls, the problem you are describing fits the charicteristics of an ignitor issue almost to a tee, stalls hot and wont restart till it cools down some,
first thing you need to do is when it stalls verify there is no spark, if it has spark then I would lean towards fuel. but usually when its a fuel issue it feels like its running out of gas, first lack of power, then sputtering then it dies, what your describing is pretty much instant stalling which leads to a spark problem, easy way to check for spark is if you have a timing light or can borrow one hook it up to any plug wire and watch for light flash as your cranking, if there is no spark then the timing lights inductive pick-up will not sense and the light will not flash, if it does flash you got spark.
hope this helps

Also have you gone back through the install and made sure of all connections and double check all the engine grounds as well if they are dirty or corroded they may not be able to supply the extra demand from the new system
 
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