3.0 Mercruiser seems to hang or seize when starting

[dubs283]

Why jump ahead, just do the basics first..

Pragmatic advice seems to fall on deaf ears around here lately

 

[stang32]

Why jump ahead, just do the basics first...most all have ask you to pull the plugs and see if it will turn over first...gotta do testing in some order or you wont know what the real issue is...

exactly, i am sitting here reading his post about i guess i will pull the drive tomorrow and i am Yelling at my computer " PULL THE F!@#ING SPARK PLUGS. lol

 

[michael0610]

exactly, i am sitting here reading his post about i guess i will pull the drive tomorrow and i am Yelling at my computer " PULL THE F!@#ING SPARK PLUGS. lol

Ok. Motor is freed up and turning. I'm on to changing any fluids necessary and putting plugs back again.

 

[michael0610]

Ok. Motor is freed up and turning. I'm on to changing any fluids necessary and putting plugs back again.

Just to clarify. I had already taken the plugs out and tried to turn the motor by hand using the alternator pulley method but that didn't work. I was concerned about trying it with the starter for fear of potentially breaking a piston arm or damaging valves when several others started talking about dropping the drive. I went for broke (no pun intended) and tried the starter. It hung for an instant on the first and second attempts. On the third attempt, she freed up and turned steadily. I'm going to drain the crankcase and get fresh oil in it, seafoam the cylinders and re-install the plugs.

 

[airshot]

Instead of sea foam, get storage oil, fogging oil etc. for the cylinders. You might do a compression check while you have the plugs out.

 

[michael0610]

Instead of sea foam, get storage oil, fogging oil etc. for the cylinders. You might do a compression check while you have the plugs out.

Ok. I popped the drain plug and have water in my oil. Not sure where to go with this. I can refill it with fresh oil and do a compression check. Any other advice?

 

[Scott Danforth]

Ok. I popped the drain plug and have water in my oil. Not sure where to go with this. I can refill it with fresh oil and do a compression check. Any other advice?

Pressure check your cooling system. My guess..... improper winterizing

 

[stang32]

when you cranked it with the starter, were the plugs in or out?
you may have damage to the manifold or worse, the block due to freezing water however, if you were attempting to start it on muffs and let the water run for an extended period of time water may have made its way into the cylinders and past the rings.

 

[michael0610]

when you cranked it with the starter, were the plugs in or out?
you may have damage to the manifold or worse, the block due to freezing water however, if you were attempting to start it on muffs and let the water run for an extended period of time water may have made its way into the cylinders and past the rings.

The plugs were out. When I last shut it down over three years ago, I drained the block as I always have at the end of the season so I'm hoping and praying for no block damage. I see none externally but who knows on the inside. The head gasket was replaced the same year I last ran it and only has a few hours on it. All I know to do without tearing the motor apart is to fill it with fresh oil and see if she'll start with the muffs and then check the oil for contamination and go ahead and perform a compression test.

 

[michael0610]

The plugs were out. When I last shut it down over three years ago, I drained the block as I always have at the end of the season so I'm hoping and praying for no block damage. I see none externally but who knows on the inside. The head gasket was replaced the same year I last ran it and only has a few hours on it. All I know to do without tearing the motor apart is to fill it with fresh oil and see if she'll start with the muffs and then check the oil for contamination and go ahead and perform a compression test.

Also do a coolant system pressure test as Scott recommended.

 

[nola mike]

How much oil? Change it and run it. If it comes back might be new block time

The plugs were out. When I last shut it down over three years ago, I drained the block as I always have at the end of the season so I'm hoping and praying for no block damage. I see none externally but who knows on the inside. The head gasket was replaced the same year I last ran it and only has a few hours on it. All I know to do without tearing the motor apart is to fill it with fresh oil and see if she'll start with the muffs and then check the oil for contamination and go ahead and perform a compression test.

Good first step

 

[michael0610]

How much oil? Change it and run it. If it comes back might be new block time
Good first step

Changed the oil and filter. It turns over but won't start. looks like a bad coil pack so I've got one coming tomorrow.

 

[Scott Danforth]

Changed the oil and filter. It turns over but won't start. looks like a bad coil pack so I've got one coming tomorrow.

You may want to do some troubleshooting. coils rarely if ever go bad.

 

[stang32]

it may take several oil changes to get all the water/milky oil out.

 

[michael0610]

Ok. I'm finally back. Here is the situation. I have changed all of the following:

1. New battery
2. New Starter Solenoid
3. New Starter
4. New Spark plugs
5. New carburetor
6. New Distributor Cap
7. New Rotor
8. New coil pack

I did all of this primarily because it is a 20 year old boat and it sat for over three years.
Additionally, I flushed the fuel tank and refilled with non-ethanol gas, changed the engine oil, and lower unit fluid (Understanding this should have no effect on engine start). The only thing I haven't done is check/change the distributor itself and have not checked resistance on the on/off safety switch but the engine turns freely and at times seems to want to fire. Also tested for fire with a spark tester and it was positive. Any thoughts?

 

[Scott Danforth]

What trouble shooting did you do? If you have points style dizzy, you need to service the points

Did you check for signs of water in the cylinders?

 

[michael0610]

What trouble shooting did you do? If you have points style dizzy, you need to service the points

Did you check for signs of water in the cylinders?

If I'm getting spark on the spark tester points shouldn't be an issue correct?
As for water in the cylinders I don't know to check for that. Thanks Scott

 

[Scott Danforth]

If I'm getting spark on the spark tester points shouldn't be an issue correct?

Wrong

Points need to be serviced every year. Dwell set and then timing set.

 

[nola mike]

Wrong

Points need to be serviced every year. Dwell set and then timing set.

How does strong spark at the plugs not rule out the points? Need to check timing, compression, plug wire order, make sure you're getting fuel down the carb throat. Op changed too many variables at once on a non starting engine, so now you don't know whether one of your new parts is bad/not installed/not adjusted correctly

 

[Scott Danforth]

How does strong spark at the plugs not rule out the points? Need to check timing, compression, plug wire order, make sure you're getting fuel down the carb throat. Op changed too many variables at once on a non starting engine, so now you don't know whether one of your new parts is bad/not installed/not adjusted correctly

if dwell is not properly set, timing cant properly be set with points.

no money is even spent on setting points. just 5 minutes of time to get the beer, dwell meter, screw drive and remote start button