Mercruiser 4.3 removing oil from bores?

[Superjetjim]

Hi, I’m just being a 4.3 out of long term storage (19yrs!) I squirted a couple of shots of engine oil into each plug hole to help with initial turn over - the motor is now free and turning over with good (albeit high, due to the residual oil) compression.
The motor spins over freely on the (new) starter for compression test - but with all plugs back in it barely, if at all turns due to the high comp I guess.

How would you suggest I clean this engine oil out of the bores? Perhaps spray carb cleaner into the plug holes to clean it out as it turns over?

One pot is lower compression than the others, suspecting that valve might need a lap?

Thanks!

 

[nola mike]

Spin it with the plugs out, any oil will be expelled through the plug holes. Although if it's turning over, any oil will go out the exhaust anyway. I'd run it for a while and recheck the compression.

 

[Superjetjim]

Spin it with the plugs out, any oil will be expelled through the plug holes. Although if it's turning over, any oil will go out the exhaust anyway. I'd run it for a while and recheck the compression.

Thanks Mike, that was my intention but it’s not turning over due to the high compression with the plugs in. Plugs out I’ve expelled as much as I can with plugs out, just need to thin down what’s in there to get it out. Maybe carb cleaner is the answer? Or perhaps some thinner fogging oil might help?

 

[nola mike]

Thanks Mike, that was my intention but it’s not turning over due to the high compression with the plugs in. Plugs out I’ve expelled as much as I can with plugs out, just need to thin down what’s in there to get it out. Maybe carb cleaner is the answer?

No, you have another issue. Oil residue isn't enough to keep the engine from turning over. If it isn't turning over at all, I would check to make sure that your valves are moving in that low compression cylinder. Otherwise, start with cleaning your connections and load testing your battery

 

[Superjetjim]

No, you have another issue. Oil residue isn't enough to keep the engine from turning over. If it isn't turning over at all, I would check to make sure that your valves are moving in that low compression cylinder. Otherwise, start with cleaning your connections and load testing your battery

I think you might be onto something on the connections, I’ll check them next. I’ve just fitted a brand new starter so it won’t be that, battery is a new high end YUASA. It’s spins over easily without the plugs in the pots and valves / rockers are all going up/down.

So 185PSI isn’t too high for it to turn over OK?

Hoping my crank bearings aren’t toast and binding under compression

 

[Bondo]

Ayuh, I too, would look at the battery cables, 'n the connections, for the problem,.....

Oil wet cylinders are not yer problem,....
A new starter should Spin over at 200 psi,....

 

[Superjetjim]

Just been and re-tested with new leads. It turns over with any 3 of 6 pots with plugs in, more than that it won’t.
Also the fresh oil change this week now looks like this. I suspect bottom end might be shot (rust discolouration in oil?)

 

[Bondo]

Just been and re-tested with new leads. It turns over with any 3 of 6 pots with plugs in, more than that it won’t.
Also the fresh oil change this week now looks like this. I suspect bottom end might be shot (rust discolouration in oil?)

Ayuh,.... Were any of the starter's electrical connections at all Hot, when it wouldn't roll the motor over,..??
If the starter system is Ok, I guess drain it, flip it over, 'n pop the pan,.....

 

[Superjetjim]

Ayuh,.... Were any of the starter's electrical connections at all Hot, when it wouldn't roll the motor over,..??
If the starter system is Ok, I guess drain it, flip it over, 'n pop the pan,.....

Yes they were, replaced with new ones and now it’s turning over strongly! Thanks

 

[Bondo]

Yes they were, replaced with new ones and now it’s turning over strongly! Thanks

Ayuh,..... When there's Heat, that means there's Resistance in the connection,......

Cleaning shiny clean is usually enough to fix the situation,.....

 

[Lou C]

A good troubleshootin’ tool is a Harbor Freight (here in Long Island we call them Horror Freight lol) IR temp gun. Use it to find high resistance circuits and terminals, sticky brake calipers, exhaust elbows that are clogging up, etc. Another good tool is a multimeter with an amp clamp this can be used to estimate your starter draw and charging amps. With this you can replace components before they fail and also if installing new battery cables you can size them according to the actual load in the starter circuit (assuming a good starter & battery).

 

[apw30534]

Just been and re-tested with new leads. It turns over with any 3 of 6 pots with plugs in, more than that it won’t.
Also the fresh oil change this week now looks like this. I suspect bottom end might be shot (rust discolouration in oil?)

Was it left outdoors to freeze with water in the block ?
Even if it was winterized or drained... just the simple fluctuations in temperature and humidity can/will cause water to get into places you dont want it.

If it has decent compression, good oil pressure and doesn't make any bearing noises... what do you have to lose ? It might be just fine.

If it were me... I would change the oil a few times to see if the discoloration clears up.
It may just be light rust from cylinder walls getting into the oil, or junk bypassing the oil filter.

If it doesn't go away... I think you know what the next step is. lol

 

[Superjetjim]

Thanks all for your help, I’ll be rebuilding the carburettor, installing the new risers, bolting it down to the pallet and trying to start it this weekend for the first time. Wish me luck!

I did have one last question, the plug socket on the engine where you connect the controls, I understand you can bypass this with two pieces of wire? Does anyone know which ports on the plug?

Think it might be 6/7/8?

 

[Superjetjim]

Was it left outdoors to freeze with water in the block ?
Even if it was winterized or drained... just the simple fluctuations in temperature and humidity can/will cause water to get into places you dont want it.

If it has decent compression, good oil pressure and doesn't make any bearing noises... what do you have to lose ? It might be just fine.

If it were me... I would change the oil a few times to see if the discoloration clears up.
It may just be light rust from cylinder walls getting into the oil, or junk bypassing the oil filter.

If it doesn't go away... I think you know what the next step is. lol

Yes thanks, hopefully when I start it this weekend it sounds okay.

I’ve dropped the oil once and quite quickly it came back as slightly cloudy rusty. Hopefully it’s just light cylinder rust as you say.
Oil doesn’t seem to be coming out of one of the pushrods particularly well compare to the others.

Can you just undo the rocker and lift the push rod out blow-carb cleaner down it and refit?

 

[Scott Danforth]

Hi, I’m just being a 4.3 out of long term storage (19yrs!) I squirted a couple of shots of engine oil into each plug hole to help with initial turn over - the motor is now free and turning over with good (albeit high, due to the residual oil) compression.
The motor spins over freely on the (new) starter for compression test - but with all plugs back in it barely, if at all turns due to the high comp I guess.

How would you suggest I clean this engine oil out of the bores? Perhaps spray carb cleaner into the plug holes to clean it out as it turns over?

One pot is lower compression than the others, suspecting that valve might need a lap?

Thanks!

stored 19 years in a climate controlled environment, or 19 years outside with a tarp over it?

 

[Superjetjim]

stored 19 years in a climate controlled environment, or 19 years outside with a tarp over it?

In a boat storage barn, with tarp I was told. Interior is immaculate and it’s only done 40hrs from new. Was winterised by a dealer when put into storage (have paperwork to support. I drained some of the fluid from the block and left in freezer overnight and it stayed as water so it’s had that at least.

 

[Scott Danforth]

boat storage barns are just a covered enclosure. the 19 years of condensation will have coated the interior of the engine a bit.

did you pull the valve covers and take a look under them?

did you drop a bore scope down the spark plug hole?

 

[nola mike]

boat storage barns are just a covered enclosure. the 19 years of condensation will have coated the interior of the engine a bit.

did you pull the valve covers and take a look under them?

did you drop a bore scope down the spark plug hole?

I mean, it really doesn't matter, does it? Change the oil, roll the dice, see what happens. Better odds with better storage, but no guarantees regardless.

 

[Scott06]

I did have one last question, the plug socket on the engine where you connect the controls, I understand you can bypass this with two pieces of wire? Does anyone know which ports on the plug?

Think it might be 6/7/8?

5/6/7 are the wires .

6 red purple is 12 v + to dash
5 purple is ignition
7 yellow /red is to engage starter solenoid and thus starter

i took two pieces of 14 gauge stranded wire , twisted two ends together and put them in 6. Stick one of the other ends in 5 for maintained power to ignition. The other momentarily bump the starter on 7 Until running. To shut off pull out wire from 5.
of course you need the large + battery cable To starter and ground on back of block / flywheel cover to be hooked up and clean of corrosion…

 

[Superjetjim]

5/6/7 are the wires .

6 red purple is 12 v + to dash
5 purple is ignition
7 yellow /red is to engage starter solenoid and thus starter

i took two pieces of 14 gauge stranded wire , twisted two ends together and put them in 6. Stick one of the other ends in 5 for maintained power to ignition. The other momentarily bump the starter on 7 Until running. To shut off pull out wire from 5.
of course you need the large + battery cable To starter and ground on back of block / flywheel cover to be hooked up and clean of corrosion…

Thanks Scott, appreciated