Working On Locked 305 V8

[Quarterwave]

Hi,

I'm working on a 1996 Mercruiser 305 V8 that has been sitting and not turned over for 10 years. I've got some Kroil soaking in the cylinders right now, but before I try to hand crank the engine via the main crankshaft bolt, how can I tell if the sterndrive is in neutral?

Or better yet, does it need to be?

Also - that main crankshaft bolt is rusty - are there any tips that anyone would be willing to share to help remove that bolt and replace it? I had to use an Easyout to remove one of the header bolts, but all the others (7) came out very easily... all 8 plugs came out fairly easily once I got access to them....

Any advice is appreciated,

 

[harleyman1975]

DO NOT use that main bolt to crank the engine. Instead use pry bar on the ring gear or remove the balancer and get the special socket that fits on the crank itself.

 

[harleyman1975]

To rule out the outdrive remove it by simply putting shift selector in fwd and then remove the 6 nuts holding the outdrive to the bell housing and slide it off.

 

[alldodge]

Boat was used for one year then sat for 10 years, I would say that is unusual.
Do you know the history as to why it sat so long? Is the motor block cracked?
If you haven't already remove the drive, because it might be the drive is locked up and not the motor

The bolt being rusty is not an issue, its just rusty, so why do you want to replace it?

 

[Quarterwave]

Thanks for the responses everyone.

Harleyman1975 - thank you for the tips. Do you have any recommendations on supporting the drive when I unbolt it so that it doesn't drop from the transom?

Alldodge - the previous owner owned a sports-fishing business in Costa Rica and decided he liked it more there than in the US and decided to make his home there. Whenever he came back to the states, the last thing he wanted to do was to take his bowrider out, so it sat idle and covered on a trailer parked on a concrete driveway in his business estate.

So far, everything that I've pulled off the engine has been pretty rusted, but I'm using it to learn about the engine as I have great interest in that. If I have to pull it out, I will and then put it on a rotisserie engine stand and strip it down for a rebuild - and farm out any parts that need to be machined. I hope I do not need to get that involved and so, my first thought was to pull the headers off to access the plugs and then to squirt some Kroil in the cylinders. I did that over the weekend and are letting it soak in until this coming weekend.... along with filling up the batteries and putting them on charge to see if they will take - and hold - a charge.

That leads me to why I asked about the main crank bolt as I'd like to try and turn the engine over and I thought it was best to do that by putting a socket on the main crank bolt and to try turning it... but according to the responses so far, that's a bad idea.

In response to your question, ideally, I do not want to remove it if I don't have to!

Any more ideas or suggestions are welcome!

 

[alldodge]

Need to know if you have an Alpha or Bravo drive. If you look on top the motor there should be a serial number of motor, transom and drive. The serial number of the drive can also be found on the side of it

For a Bravo drive
The drive is a bit heavy but will not fall off. If the drive is up, reach behind the drive and remove the speedometer tube. The tube is rubber and the fastener rotates 45 degrees and then pulls straight up and out. Its made from plastic and has an o-ring on the end.

Next put the drive all the way down and remove the two trim cylinders on the end of the drive, don't remove the ends next to the transom. Remove the six bolts holding the drive, then pull the drive off. If you place a piece of wood close to the bottom it can drop on it. The drive weight is over 120 pounds and coming off is easy, will need help to get it back on.

For Alpha drive
Same as above, but place shifter in full forward position. Drive weight is right at 85 pounds

 

[Quarterwave]

Ok, thanks for the information, AllDodge. I'll need to look at the stern drive for the serial number as I'm not sure what it is offhand.

Some quick questions if you have time:

1) It seems that the stern drive is moved via hydraulics - and the pump is associated with the motor, which isn't running. How can I move the drive up or down if it's hydraulic?

2) Are there any special tools that I'll need to re-attach the drive?

3) What type of socket or tool will I need to turn the crank?

4) Are there any specific torque settings that I need to be aware of?

 

[alldodge]

Ok, thanks for the information, AllDodge. I'll need to look at the stern drive for the serial number as I'm not sure what it is offhand.

Some quick questions if you have time:

1) It seems that the stern drive is moved via hydraulics - and the pump is associated with the motor, which isn't running. How can I move the drive up or down if it's hydraulic?

The drive is moved up/down by a 12V trim pump located on the starboard side beside the motor. You actually could unbolt the hydraulic rams off the drive and move it manually. As before its heavy but can be down. Have something nearby to block the drive in the up position to work. Be safe and make sure it wil hold the weight

2) Are there any special tools that I'll need to re-attach the drive?

Will need an alignment bar p/n 91-805475A1 and found in many places. Ebay seems to be the cheapest place

3) What type of socket or tool will I need to turn the crank?

I don't remember the size but just measure across the flats, think its something like 1 1/4
As mentioned its not good to put a lot of force on this bolt, but if you remove all the plugs and use a 1/2 drive ratchet, you won't place enough force on it to damage the bolt. Just don't add an extension to give you more leverage or use an impact wrench

4) Are there any specific torque settings that I need to be aware of?

Not currently, will need to get further along before torque specs will be necessary

 

[Quarterwave]

Got it, thank you. I'll start working on it again this weekend and will revert

I appreciate your help and insight.

 

[Bt Doctur]

DO NOT USE A CRANK NOSE BOLT, break/strip the nose bolt and your screwed

Remove the drive and get a old inputshaft and weld a "T" on it to turn the motor
Remove the front pully, reinstall longer bolts and use a bar between the bolts.
Remove the pully, harmonic balancer and use a crankshaft socket to turn the motor

 

[Bt Doctur]

https://www.summitracing.com/search/Part-Type/Crankshaft-Sockets

 

[alldodge]

BT and Harley bring up a good point IF it is the new style 7/16 bolt (item 18) Design II
http://www.mercruiserparts.com/bam/subassembly/31835/1014/300

If its the 2 inch bolt (item 18) Design I
http://www.mercruiserparts.com/bam/subassembly/31835/1014/290

Then not so much

 

[Bt Doctur]

7/16ths or 3/4 I would still not use the nose bolt . I would never use it on a running motor let alone one that sat for 10 years with a unknown winterizing
What they call 2 inch is a .750 dia bolt

 

[Scott Danforth]

NEVER and I mean NEVER attempt to turn the motor with the crank bolt. it will strip the threads and make the crank useless (meaning need to pull motor and replace crank). BTDoctur has the crank socket shown above. or pull the starter and use the ring gear teeth and a small pry bar

regarding a rusty crank bolt - doesnt matter. if there is enough rust to matter, the motor wont be worth saving.

pull the drive as mentioned. you have oil down the cylinders. if it wont turn over, your going to have to pull the motor, get it on a stand and start tearing it down. over 10 years, any cylinder with a valve open to atmosphere will have piston rings that have become one with the cylinder block

 

[Quarterwave]

Okay, thanks everyone. After having taken a couple of weekends to clear the land that I needed to store this boat, I'm going to start working on the engine this coming weekend.

So, just to clarify:

Pull the stern drive off and support (will most likely use a floor jack with wheels and a solid piece of wood, with 2 guys holding it)
Do NOT try to manually turn the engine over using the crankshaft via the bellhousing
DO try to turn the engine over using the main crankshaft bolt located at the front of the engine

Is there anything else that I'm missing to try and get the engine to turn?

 

[Bt Doctur]

DO try to turn the engine over using the main crankshaft bolt located at the front of the engine

Yep, go ahead but dont say you were not warned of what will happen

Get a old inputshaft and weld a T to it to turn the motor.
pull the starter and use a screwdriver on the ring gear
remove the harmonic balancer and get the crankshaft socket.
Then get a picture of the socket and post it where you will always see it to remind you.

 

[revkev6]

pop all the plugs out and fill the cylinders up with kroil from there.
grab onto the prop.. if it spins free... it's in neutral!
I would spray it down and see if she spins on the starter before I started taking it all apart. sounds like you haven't really tried anything yet?? give it a good cleaning, make sure its got fresh cheap oil in it and you might be surprised. is it injected or carbed?? if you pulled the exhaust already how do the valves look? rusty crusty or fairly clean? if the exhaust valves are clean... likely things will be ok inside.

I have a 305 sitting on the floor in my garage.. with the plugs out and oil in the cylinders I can grab the pulley and spin it by hand.

 

[Quarterwave]

No Title

Hi everyone,

Bt Doctor - great idea, but unfortunately I do not have a welder, and do not know how to weld!

Revkev6 - yes, that's what the plan is so that I can see what needs doing. It's a carb engine, 2 barrel Rochester. I already have the plugs out (a couple broke, but didn't look rusty) and sprayed each cylinder down with Kroil a few weeks ago. The exhaust manifolds had some flaky rust inside as did the large rubber "tubes" that lead to the transom. I haven't had a chance to look inside the cylinders yet. The center housing was rusted. Please see "Photo 1" for a sample pic.

Thank you for the tip about the propeller - I will try that out. If it does not spin, how can I get it into neutral?

In an effort to get something, I hooked up a freshly charged battery to the main terminals and was able to turn the blower motor on for a moment. After I switched the kill switch to "2" or "All" it stopped. Then, when I switched it back to "1", I got nothing. No gauges, no horn, no blower, nothing. There was an orange wire running from the starter to the alternator that got hot to the touch and some smoke came out of the alternator so I turned the kill switch to "off" and it stopped. I tried turning the key with the kill switch in every position, but wasn't able to even get a click. The multimeter didn't pull below 12.4 volts EXCEPT when the small amount of smoke was coming from the alternator.

That seemed weird to me - to get basically nothing from a fully charged battery..... for whatever it's worth, the wiring looked to be fairly "factory" looking and not beat up - no spliced wires with electrical tape etc... the connections were tight and the fuses were also ok. So, my thought was to trace each wire from the main throttle controller and go from there.

Photo 2 shows the controls near the cockpit. I've been Googling for a schematic for this make/model, but haven't come up with anything yet. Note - the red switch was tried in both the "off" and "run" positions, with the same result.

Another issue that I have is firstly, identifying the model of stern drive. Please see "Photo 3" for a close up - can anyone identify what type it is?

Secondly, I traced the wires from the main control along the starboard gunnel and into the engine compartment. Aside from the speedometer cable wire, there are no other wires running through the transom. To date, I've been under the impression that the motor that controls the "up and down" motion of the stern drive was electric. With that in mind, it seemed to me that the stern drive was controlled hydraulically and not electronically. Is that wrong?... and if the engine isn't running, how can I make the hydraulics work? Run wires straight into the hydraulic pump? Please see "Photo 4" for what I "think" is the controller for those hydraulics.

Well, that's all for now. I really appreciate all of the input from everyone and are trying to learn as best as I can.

 

[alldodge]

After seeing that the thermostat housing has rusted thru I wouldn't even try to free the motor up, that motor is toast. Suggest pull and replace or disassemble to see if it is rebuildable

If you still wish to continue, the ALT wire is heating up because the ALT is shorting out. Remove the orange wire from the starter, or remove from the ALT and tape the lug so it won't ground out.

The stern drive trim pump runs off of battery voltage and is controlled by the throttle handle. There are several wires going from the motor and trim pump up to the helm.

 

[revkev6]

Well... from the pic of the motor it looks like the raw water manifold is rusted right through? Not a great sign.

Looks like you have an alpha one gen ii. Outdrive.

Pic 4 is the electric powered hydraulic trim pump that moves the outdrive up and down. There us a switch on the throttle/shifter that actuates it.

As for the smoking alternator I don't have much of an idea... are you 100% sure you have black to positive and red to negative?

I would connect only the starter and engine ground at first right now and manually jump the starter to see if you get anything.