Chrysler 105hp - Stalling randomly

[George Pan]

My engine stalling randomly .

I have change CDI 2 months now with a MSD streetfire . All seems ok except some times that engine bogs and stalls. After this is not starting again . After 30-50 minutes is starting ok and perfoms perfect.

I have clean the carbs .
check the timing
check the fuel lines
all are ok .

Last time that i had the same symptom . When i open the cowl and touch somewhere at the bottom of the engine i got a strike from voltage .

So did a check and see that i have too much water getting inside from the cover maybe .

Could this be a reason for the stalling ?

 

[Fishing in driveway]

Check your compression had a similar issue with 1996 112HP Evinrude turns out both head gaskets were blown 110 to 120 should be the number you're looking for.

 

[Nordin]

When it stalls, have you check if it has spark then? As you have change to MSD streetfire, you suppose to have beltdriven distributer ignition system.

Does the distributer have preamp or points? If you do not have spark when it stalls there maybe is an issue with the preamp.

You say that you got a strike of voltage from the bottom of the cowl.
That is not okey!! Check all wires for bad isolation, there maybe is an bad isolation that comes an goes. It will definitely give you problem with the ignition because the MSD need 12VDC to work properly.

Do I misunderstand you or not but is there water in the lower cowl?? Please, explain more about it.

 

[George Pan]

I am not sure if i have spark... maybe is not toο strong. . When i try to restart if keep the starter is like to try start but if i left the switch dies .


Yes i have water in the engine . When i trim down i have to much spray of water. I inspect the cowl and i see that at the front part is not tight when is closed .

 

[George Pan]

No Title

 

[Nordin]

I am just thinking about the exhaustboot in the lower midlegcover
If it is leaking you get coolingwater and exhaust in the enginecover.

The boot holds in place by a big hoseclamp. Maybe it is broken by rust or the boot has get dry and leak.

 

[George Pan]

I check for the water leak . For sure is not from inside . Is coming from outside not too much but maybe is enough to make trouble.

i am thinking now ...

1) coil
2) pre amp
3) Starter solenoid ( was the place that i got the strike from voltage, and was wet from water)

 

[George Pan]

UPDATE !!!!

Last trip

Cleaned carbs . Make to cowl some mods for the water.

Still the same problem with rough idle now .

I change the coil and ...... all seems fine for the time .

I call MSD local dealer and ask him if is possible Streetfire blown my coil . He said me is very possible because these older coils are from oil and the power from MSD is stronger.

So suggest me to replace the stock coil with MSD Blaster High Vibration . The big difference is that inside has epoxy against to oil . Is more durable etc etc . ....

What do you believe ?

 

[Nordin]

As you modified the ign.system with a MSD I will suggest to change to an ignition coil that is adapted for the MSD.
Maybe you have to change the plugs too if you have surface gap typ.

Regular battery ignition system with points for OB has an ignition coil with a secondary resistance about 7-8Kohm.

Automotive typ coil for points has sec.resistance about 10-11Kohm.

The stock Motorola CD system has an sec.resistance of the ignition coil 500-600 ohm.

You see there is a big difference and it maybe will be the issue. Since the coil will warm up during performance there can be problem for the ignition coil to produce spark.

Another thing to have in mind.
I have seen a video on Youtube and there they modifiy a 105Hp to MSD. They also put the MSD circuitbord into the old Motorola box.
I think that they in this video made an electronic circuit to adapt the trigger signal from the preamp to fit the MSD.

BUT I am not 100% sure. It is long time gone since I watched it.

 

[George Pan]

As you modified the ign.system with a MSD I will suggest to change to an ignition coil that is adapted for the MSD.
Maybe you have to change the plugs too if you have surface gap typ.

Regular battery ignition system with points for OB has an ignition coil with a secondary resistance about 7-8Kohm.

Automotive typ coil for points has sec.resistance about 10-11Kohm.

The stock Motorola CD system has an sec.resistance of the ignition coil 500-600 ohm.

You see there is a big difference and it maybe will be the issue. Since the coil will warm up during performance there can be problem for the ignition coil to produce spark.

Another thing to have in mind.
I have seen a video on Youtube and there they modifiy a 105Hp to MSD. They also put the MSD circuitbord into the old Motorola box.
I think that they in this video made an electronic circuit to adapt the trigger signal from the preamp to fit the MSD.

BUT I am not 100% sure. It is long time gone since I watched it.

Nordin thanks for your help . I haven't any info from stock CDI and coil . I will appreciate if you check the specs of MSD and give me your opinion .

I had a communication with the guy from youtube . He just replace Magnapower with Streefire. Msd accept signal for both points and magnetic applications .He used directly the points signal with stock preamp. He used also stock coil and plugs.
For this reason i kept the stock coil but i am not sure if he test it for big period like me .

Streetfire specs

Spark Energy:	95 MJ Per Spark
Primary Voltage:	435 Volts
Secondary Voltage:	45,000 Volts
Spark Series Duration:	20? Crankshaft Rotation
RPM Range:	15,000 RPM with 14.4 Volts
Voltage Required:	10-18 Volts, Negative Ground
Current Draw:	.7Amp per 1,000 RPM
Weight & Size:	1.5 LBS. 6"Lx3.5"Wx1.75"H

Blaster High vibration coil specs

Turns ratio:100:1
Primary resistance: .7 OHMs
Secondary resistance:4.5K OHMs
Inductance:8 mH
Maximum voltage:45,000
VoltsPeak current:140 mA
Spark duration:350 uS

 

[Nordin]

George Pan ......you have the spec. in the last sentences.

Turns ratio:100:1
Primary resistance: .7 OHMs
Secondary resistance:4.5K OHMs
Inductance:8 mH
Maximum voltage:45,000
VoltsPeak current:140 mA
Spark duration:350 uS

SEC.RESISTENCE 4,5Kohm. That is about 10 times higher then stock coil.

If you are able to find a used automotive coil from a yunkyard and have a multimeter to measure the sec.winding, it maybe will be woth a try.

 

[George Pan]

George Pan ......you have the spec. in the last sentences.

Turns ratio:100:1
Primary resistance: .7 OHMs
Secondary resistance:4.5K OHMs
Inductance:8 mH
Maximum voltage:45,000
VoltsPeak current:140 mA
Spark duration:350 uS

SEC.RESISTENCE 4,5Kohm. That is about 10 times higher then stock coil.

If you are able to find a used automotive coil from a yunkyard and have a multimeter to measure the sec.winding, it maybe will be woth a try.

If i change from surface gap to projected is Champion QL78YC a good alternative ?

 

[George Pan]

No Title

Almost ready . Tomorrow i will go for test ride.