i just bought hunter 27 with yanmar sb8 they said it was rebuilt with 4hr on rebuild so i went out and ran the motor 25 miles and it stalied thought i ran out of fule but that was not it to my surprse it ran out of oil it somked very little it had no oil leak they just put a new head on it and yes it was full of oil when i srated is it comen for yanmars to go through oil or was there to much compression for rings with new head and does sb8 have a piston liner or does yhe block need to be bored
run out of oil
- Thread starter Luc B
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I hope the engine did not seize up.
Either your oil system has a leak or you have a bad problem with the engine burning oil.
If there is a leak in the oil system you will need to find it. One place to check is the raw water pump which usually has an oil seal fitting.
Get those white oil absorbent pads and place them around your engine after you fill it back up with oil. If oil is dripping out it will be easy to see on the white oil pads.
You better hope you don't need the cylinders re-bored and a ring job.
Either your oil system has a leak or you have a bad problem with the engine burning oil.
If there is a leak in the oil system you will need to find it. One place to check is the raw water pump which usually has an oil seal fitting.
Get those white oil absorbent pads and place them around your engine after you fill it back up with oil. If oil is dripping out it will be easy to see on the white oil pads.
You better hope you don't need the cylinders re-bored and a ring job.
no it did not seize and no leeks and i just put a inpala in i think it is rings when oil filler cap off it has crank case pressure wihich i think it means compression is getting by the rings if it needs piston does it have a cylinder sleeve or does it need to come out and be bored and can you get over sized piston
If the oil is not ending up in the catch pan under engine. Then it must be going out into the raw water exhausts wet discharge. You did not say if it was smoking badly. If it was smoking badly then the oil would have to leaking into the cylinders and is being burned up and sent out the exhaust.
What grade of oil were you using? A well worn diesel will operate best with a 15W40 SAE and on occassions with a thickening additive. This will reduce oil burning and increase compression. White smoke coming out the exaust is a tell tale for oil burning.
I would check with whoever was supposed to "rebuild" the engine. Obviously there was something that was not done correctly. Much of the work on these small Yanmar can be done in the boat.
If it is not leaking out into the boat, then I would go to the thing they worked on first.. A new head .. If they didn't replace the valve guides or ream them correctly, or did not correctly install the intake valve seals, it would do what you are describing.. after that, piston rings .. I will echo that something in the rebuild was not done correctly..
I had this same exact problem on my Yanmar yse12. I understand yours is a ysb8. My engine was using a quart of oil every 10 miles. About the same as yours. There was no smoke out the exhaust. Took me a while to figure it out, but the engine was using the oil for fuel. Diesels love there oil... heh heh. It was being forced past the rings into the combustion chamber.
I understand you had a rebuild and everything should be right, but it is not. Anyway, replacing the piston is an easy task. Just remove the head, remove the plate on the opposite side, undo the bearing and push the piston out on the head side. I purchased a new piston and rings for $100. I reamed out the cylinder wall. I installed the new piston and it has burned very little oil over the last 10 years. Sean
* BTW, the biggest problem I had with the engine was starting problems. Fought that for a couple of years. Replacing the fuel pump totally fixed that problem. Starts every time in 2 seconds.
I understand you had a rebuild and everything should be right, but it is not. Anyway, replacing the piston is an easy task. Just remove the head, remove the plate on the opposite side, undo the bearing and push the piston out on the head side. I purchased a new piston and rings for $100. I reamed out the cylinder wall. I installed the new piston and it has burned very little oil over the last 10 years. Sean
* BTW, the biggest problem I had with the engine was starting problems. Fought that for a couple of years. Replacing the fuel pump totally fixed that problem. Starts every time in 2 seconds.
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