Filled a Honda 5hp cylinder with gear oil...

hobnob · 22 April 2011, 21:36

as I had run out of fogging oil last autumn. Any precautions to take on start-up?

jwalker · 22 April 2011, 23:12

Remove the spark plugs and spin the engine over to ensure you remove excess oil then fire it up as normal.

hobnob · 24 April 2011, 18:32

Thanks - I guess a bit in the sump won't do any harm...

Peter_C · 25 April 2011, 18:57

To burn out gear oil is going to take forever and a few spark plugs. I would recommend cleaning it out with chemicals by removing the spark plug, putting the cylinder at the bottom, pouring chemical in (Think thinner like acetone), then putting the spark plug back in. Flip the motor, shake it around, then remove spark plug and drain contents into a recycling container for oil. Now spray a light weight oil in to lightly lube the cylinder wall before starting it. Spin it over a few times with the plug out, then start it up.

The other question becomes how much leaked into places it shouldn't have and do you need to remove it before attempting to start the motor.

Matt · 26 April 2011, 12:03

I certainly wouldn't be flushing my motor out with acetone. I'd do exactly as jw suggests.

Peter_C · 27 April 2011, 05:39

Quote:

Originally Posted by Matt

I certainly wouldn't be flushing my motor out with acetone. I'd do exactly as jw suggests.

Can you give a reason why not?

The oil must be removed, or it will smoke for a very long long time. I have seen it with automotive engines where the cylinder is filled with engine oil (Often from a wet compression test). It takes a long time to stop smoking, even leaving clouds as you drive down the street. Chemicals that would be considered thinners are not going to harm the metal. What would you think of using rubbing alcohol?

hobnob · 27 April 2011, 21:56

Quote:

Originally Posted by Peter_C

Can you give a reason why not?

The oil must be removed, or it will smoke for a very long long time. I have seen it with automotive engines where the cylinder is filled with engine oil (Often from a wet compression test). It takes a long time to stop smoking, even leaving clouds as you drive down the street. Chemicals that would be considered thinners are not going to harm the metal. What would you think of using rubbing alcohol?

I'm thinking 100cc of petrol - if I can afford it!

jezza2011 · 08 May 2011, 18:28

Hmm isnt gear oil nasty ?

I have never used fogging oil.

As the fuel oil mix is vital to engine lubrication I dont run it without the fuel connected until it stops like it tells you to.
Instead I flood the engine and leave the fuel lines with fuel still connected up.
The engine is 20 years old now and when it was last serviced 4 years ago at a dealers the compression was as good as a new engine. ( there quote) .
At the start of a season i remove the plugs, spray in some wd40 in to each pot, hand crank it over for a few mins.
Then refit plugs and crank her up.
Never had any issues.
Still starts first time and runs very very smoothly

Nos4r2 · 08 May 2011, 18:51

Quote:

Originally Posted by jezza2011

Hmm isnt gear oil nasty ?

I have never used fogging oil.

As the fuel oil mix is vital to engine lubrication I dont run it without the fuel connected until it stops like it tells you to.
Instead I flood the engine and leave the fuel lines with fuel still connected up.
The engine is 20 years old now and when it was last serviced 4 years ago at a dealers the compression was as good as a new engine. ( there quote) .
At the start of a season i remove the plugs, spray in some wd40 in to each pot, hand crank it over for a few mins.
Then refit plugs and crank her up.
Never had any issues.
Still starts first time and runs very very smoothly

Yes, but the thread is about a 4 stroke.

I wouldn't put acetone in the cylinder either. You don't know quite how oil seals (valve stem seals etc) will react to it.

Petrol is a far safer option.

Bigmuz7 · 08 May 2011, 22:11

Quote:

Originally Posted by Peter_C

Can you give a reason why not?

Because oil will build up a natural glaze in the liners as its supposed to do which aids its function .. if you stick something like acetone in there it will strip all that off and give you a metal to metal bearing surface very quickly, .. which is not my idea of what an engine needs

doggypaddle · 09 May 2011, 20:33

EP additives in Gear oil can attack white metal and babbit bearings.
best kept well away from engines!