This is a problem that I can't seem to conquer. Hopefully someone has a
suggestion for me.

I have a Mercruiser Alpha One 3.0LX with the Electronic Spark Timing on the
distributor. In recent years, I find that the engine floods out or
hesitates easily when I shower down on the throttle. So, I'm assuming that
the timing is a bit off because when running idle or high RPMs steady, it
runs smoothly. Anyway, I'd like to bypass the EST to at least check it (no
one has in a long while).

I have a (Chiltons) manual and I have referenced the Mercruiser shop manual.
However, both say that after you've jumpered the 2 white wires on the 3 pin
plug of the distributor base (step 2), you should then disconnect the
harness wires from the shift cut out switch and then connect these together
(basically applying 12V purple lead to the 3rd pin of the 3 pin plug of
the distributor white w/ green stripe lead. This is where the problem
occurs. Upon connecting these two together, the motor cuts out completely
(rather than retarding the spark to 1dg BTC).

This is the technique I'm following (from the Merc shop manual):
========
1. Start engine and allow it to reach proper operating temperature.

2. With engine running, install a jumper wire across the two WHITE leads
on the distributor using (91-818812a1), or fabricate one using a 6 in. (150
mm).
section of 16 GA wire using two male bullet terminal ends connected.

3. Bypass the shift interrupter switch by disconnecting wires at the shift
interrupt switch.
Temporarily join the engine harness wires together ( the wires you unplugged
from the switch).

IMPORTANT: Do not fail to reconnect these two wires to the shift interrupt
switch when timing
procedures are complete.

4. With timing light connected, check timing. Timing should be 1 degree
BTDC.

5. If required, loosen distributor hold down clamp and rotate distributor to
obtain specified timing.

6. Secure distributor hold down clamp, and recheck timing as above.

7. Reconnect the two wires to the shift interrupt switch. Remove jumper wire
at distributor white leads.

IMPORTANT: Be sure to remove jumper wire before returning engine to service,
otherwise timing will
not advance.

8. With timing light still connected and engine running at IDLE, verify that
timing did advance to 12 deg
BTDC (plus or minus 2 degrees).
At 2400-2800 RPM maximum advance is obtained and should be 27 degrees BTDC
(plus or minus 2 deg).
=========

Can anyone tell me whether I'm doing something wrong? Or is it that my EST
is advancing the spark to where it needs to be for idle or smooth run, but
upon disabling it, the spark is so retarded that the engine won't run?

When running at idle (w/ spark advance) it registers 13dg BTC. But it only
seems to advance to about 18 - 20 dg BTC when pushed to 2500 RPMs.

Thanks in advance,
Patrick M. Ring
ospam
webhost: www.classicmako.com

Some people set it where they want it at high rpm and then see if it idles
ok. And once it advances fully it will not advance further so you can push
the rpm up a little to make sure you are at max advance. Does it have a
knock detector? They will retard automatically if the octane is low and the
engine pings.

"Patrick M. Ring" wrote in message
...
This is a problem that I can't seem to conquer. Hopefully someone has a
suggestion for me.

I have a Mercruiser Alpha One 3.0LX with the Electronic Spark Timing on
the
distributor. In recent years, I find that the engine floods out or
hesitates easily when I shower down on the throttle. So, I'm assuming
that
the timing is a bit off because when running idle or high RPMs steady, it
runs smoothly. Anyway, I'd like to bypass the EST to at least check it
(no
one has in a long while).

I have a (Chiltons) manual and I have referenced the Mercruiser shop
manual.
However, both say that after you've jumpered the 2 white wires on the 3
pin
plug of the distributor base (step 2), you should then disconnect the
harness wires from the shift cut out switch and then connect these
together
(basically applying 12V purple lead to the 3rd pin of the 3 pin plug of
the distributor white w/ green stripe lead. This is where the problem
occurs. Upon connecting these two together, the motor cuts out completely
(rather than retarding the spark to 1dg BTC).

This is the technique I'm following (from the Merc shop manual):
========
1. Start engine and allow it to reach proper operating temperature.

2. With engine running, install a jumper wire across the two WHITE leads
on the distributor using (91-818812a1), or fabricate one using a 6 in.
(150
mm).
section of 16 GA wire using two male bullet terminal ends connected.

3. Bypass the shift interrupter switch by disconnecting wires at the shift
interrupt switch.
Temporarily join the engine harness wires together ( the wires you
unplugged
from the switch).

IMPORTANT: Do not fail to reconnect these two wires to the shift interrupt
switch when timing
procedures are complete.

4. With timing light connected, check timing. Timing should be 1 degree
BTDC.

5. If required, loosen distributor hold down clamp and rotate distributor
to
obtain specified timing.

6. Secure distributor hold down clamp, and recheck timing as above.

7. Reconnect the two wires to the shift interrupt switch. Remove jumper
wire
at distributor white leads.

IMPORTANT: Be sure to remove jumper wire before returning engine to
service,
otherwise timing will
not advance.

8. With timing light still connected and engine running at IDLE, verify
that
timing did advance to 12 deg
BTDC (plus or minus 2 degrees).
At 2400-2800 RPM maximum advance is obtained and should be 27 degrees BTDC
(plus or minus 2 deg).
=========

Can anyone tell me whether I'm doing something wrong? Or is it that my EST
is advancing the spark to where it needs to be for idle or smooth run, but
upon disabling it, the spark is so retarded that the engine won't run?

When running at idle (w/ spark advance) it registers 13dg BTC. But it
only
seems to advance to about 18 - 20 dg BTC when pushed to 2500 RPMs.

Thanks in advance,
Patrick M. Ring
ospam
webhost: www.classicmako.com

"Patrick M. Ring" wrote in message
...
This is a problem that I can't seem to conquer. Hopefully someone has a
suggestion for me.

I have a Mercruiser Alpha One 3.0LX with the Electronic Spark Timing on
the
distributor. In recent years, I find that the engine floods out or
hesitates easily when I shower down on the throttle. So, I'm assuming
that
the timing is a bit off because when running idle or high RPMs steady, it
runs smoothly. Anyway, I'd like to bypass the EST to at least check it
(no
one has in a long while).

I have a (Chiltons) manual and I have referenced the Mercruiser shop
manual.
However, both say that after you've jumpered the 2 white wires on the 3
pin
plug of the distributor base (step 2), you should then disconnect the
harness wires from the shift cut out switch and then connect these
together
(basically applying 12V purple lead to the 3rd pin of the 3 pin plug of
the distributor white w/ green stripe lead. This is where the problem
occurs. Upon connecting these two together, the motor cuts out completely
(rather than retarding the spark to 1dg BTC).

This is the technique I'm following (from the Merc shop manual):
========
1. Start engine and allow it to reach proper operating temperature.

2. With engine running, install a jumper wire across the two WHITE leads
on the distributor using (91-818812a1), or fabricate one using a 6 in.
(150
mm).
section of 16 GA wire using two male bullet terminal ends connected.

3. Bypass the shift interrupter switch by disconnecting wires at the shift
interrupt switch.
Temporarily join the engine harness wires together ( the wires you
unplugged
from the switch).

IMPORTANT: Do not fail to reconnect these two wires to the shift interrupt
switch when timing
procedures are complete.

4. With timing light connected, check timing. Timing should be 1 degree
BTDC.

5. If required, loosen distributor hold down clamp and rotate distributor
to
obtain specified timing.

6. Secure distributor hold down clamp, and recheck timing as above.

7. Reconnect the two wires to the shift interrupt switch. Remove jumper
wire
at distributor white leads.

IMPORTANT: Be sure to remove jumper wire before returning engine to
service,
otherwise timing will
not advance.

8. With timing light still connected and engine running at IDLE, verify
that
timing did advance to 12 deg
BTDC (plus or minus 2 degrees).
At 2400-2800 RPM maximum advance is obtained and should be 27 degrees BTDC
(plus or minus 2 deg).
=========

Can anyone tell me whether I'm doing something wrong? Or is it that my EST
is advancing the spark to where it needs to be for idle or smooth run, but
upon disabling it, the spark is so retarded that the engine won't run?

When running at idle (w/ spark advance) it registers 13dg BTC. But it
only
seems to advance to about 18 - 20 dg BTC when pushed to 2500 RPMs.

Thanks in advance,
Patrick M. Ring
ospam
webhost: www.classicmako.com


I have not worked on the EST but I will offer my opinion anyway.
You might try giving it a little more RPM to see if the full advance comes
into spec.
I do think your problem might be carb. related. A weak accelerator pump
would cause those symptoms. Also check your idle mixture and idle speed.
Jim

I'm having the same problem trying to put my 1996 3.0LX Mercruiser into base timing mode. It will not styart if I connect the cut off switch leads with engine off, or it will shut down while running. I have already replaced the ignition module (2days old) distr cap, rotor, all whiles, plugs, carb rebuilt pross, new starter. What next??

Check your Iginition module. I just put my old one in and connected the shut off leads together and the engine stayed running. I couldn't get it into base timing mode cuz my module is defective in that area, but it did stay running. O riginally I replaced my ignition module because it was over heating and shutting the engine down in the water leaving me stranded until it cooled down and then it would run, So I'm going to try another one and see what happens. My main concern then will be, Why or what would be causing the module to heat up and short out.

Hope this helps