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openseas 07-04-2020 20:19

Yanmar engine Seized in a sailboat
 
Hi all,

I have a sailboat with a Yanmar engine 2QM15 ( 1980 model, 15hp). The boat was on a dry dock for 12 years straight. When I used the boat last, the engine ran normal.

Yesterday, I changed the oil and filter, thermostat and water pump, fuel filter and drained old diesel.

I disconnected the hose that comes from the seacock to the water pump, and connected the water pump to a garden faucet through a hose, and tightened the hose with with a clamp. I opened the water, then started the engine, and it ran immediately. I let it run for 15 minutes, then I turned off the engine, then the water.

Today I tried to start the engine the same way. The engine turned half a round and locked. I turned off the water, then removed the air filter and box, since I found water coming out from that area, as I tried to crank the engine manually to the right and left slowly, the water was coming out of the air filter area in pulses as I was cranking it, repeated this few times, till no water came out, and the engine would crank again complete round.
I opened the garden hose again, but not all the way this time, and I started the engine, after few attempts, it ran like normal.
I let it run for 10 minutes and turned it off.
My question is:

- How the water can go inside the cylinder from the cooling system?
- Will the water stay there and cause later damage?
- Should I do anything further?
I don't know much about mechanic, and I need your help.

Thank you in Advance,

Andy

Bill Seal 07-04-2020 20:38

Re: Yanmar engine Seized in a sailboat
 
NEVER force water into the raw water intake. Without the engine running, it can back up into the exhaust manifold and hydrolock the engine. :banghead: If you got it running again, consider yourself damn lucky. Next time, put the intake hose into a bucket of water.

Wotname 07-04-2020 21:00

Re: Yanmar engine Seized in a sailboat
 
Quote:

Originally Posted by openseas (Post 3111699)
Hi all,

I have a sailboat with a Yanmar engine 2QM15 ( 1980 model, 15hp). The boat was on a dry dock for 12 years straight. When I used the boat last, the engine ran normal.

Yesterday, I changed the oil and filter, thermostat and water pump, fuel filter and drained old diesel.

I disconnected the hose that comes from the seacock to the water pump, and connected the water pump to a garden faucet through a hose, and tightened the hose with with a clamp. I opened the water, then started the engine, and it ran immediately. I let it run for 15 minutes, then I turned off the engine, then the water.

Today I tried to start the engine the same way. The engine turned half a round and locked. I turned off the water, then removed the air filter and box, since I found water coming out from that area, as I tried to crank the engine manually to the right and left slowly, the water was coming out of the air filter area in pulses as I was cranking it, repeated this few times, till no water came out, and the engine would crank again complete round.
I opened the garden hose again, but not all the way this time, and I started the engine, after few attempts, it ran like normal.
I let it run for 10 minutes and turned it off.
My question is:

- How the water can go inside the cylinder from the cooling system?
- Will the water stay there and cause later damage?
- Should I do anything further?
I don't know much about mechanic, and I need your help.

Thank you in Advance,

Andy

Andy, you might have just dodged a bullet. Take heed of what Bill Seal said!

Always suck water from a bucket and use the hose to keep the bucket full.

What you need to do next is to run the engine for at least 30 minutes at around 1200 to 1500 rpm.
Then check the oil for any water contamination (it turns milky). If it has, change the oil and filter again.
Ideally you should run the engine under load if possible but you have to be in the water to do that.
If you can launch soonish, run the engine at near full throttle in gear while tied to the dock (if necessary).
If it runs OK under load and no smoke etc, then you should be right. The 2QM15 is a reasonably tough simple engine.

openseas 07-04-2020 21:49

Re: Yanmar engine Seized in a sailboat
 
Quote:

Originally Posted by Bill Seal (Post 3111707)
NEVER force water into the raw water intake. Without the engine running, it can back up into the exhaust manifold and hydrolock the engine. :banghead: If you got it running again, consider yourself damn lucky. Next time, put the intake hose into a bucket of water.

Thank you Bill for the excellent advice, I learned something new today.

openseas 07-04-2020 22:14

Re: Yanmar engine Seized in a sailboat
 
Quote:

Originally Posted by Wotname (Post 3111718)
Andy, you might have just dodged a bullet. Take heed of what Bill Seal said!

Always suck water from a bucket and use the hose to keep the bucket full.

What you need to do next is to run the engine for at least 30 minutes at around 1200 to 1500 rpm.
Then check the oil for any water contamination (it turns milky). If it has, change the oil and filter again.
Ideally you should run the engine under load if possible but you have to be in the water to do that.
If you can launch soonish, run the engine at near full throttle in gear while tied to the dock (if necessary).
If it runs OK under load and no smoke etc, then you should be right. The 2QM15 is a reasonably tough simple engine.

Thank you so much,

Thumbs Up 08-04-2020 07:18

Re: Yanmar engine Seized in a sailboat
 
First you need to get all of the water out. Then you should change the oil. Then run it hot. Then change the oil again.

Cadence 08-04-2020 10:03

Re: Yanmar engine Seized in a sailboat
 
I believe the first 5 answers, answered the question.

gbowen 08-04-2020 11:01

Re: Yanmar engine Seized in a sailboat
 
I think there is more to this. I had my boat on the hard for 5 years and ran the engine frequently with a garden hose in the raw water intake. It was a Yanmar 3QM model. That model came with a siphon breaker in the cooling water circuit. I am building another boat now with a new 2YM15 engine now installed. There was no siphon breaker in the cooling water elbow so I drilled and tapped and put one in. There is a sticker on the motor stating hydrolift mufflers can ruin your engine.

My old Yanmar would start first pop and the wet exhaust system worked great. I could check for cooling water flow by watching the small siphon outlet outside for dribbling.

There is grave danger if your motor cranks and the engine does not start for some reason. The wet exhaust system will overload with raw water and the water backflow and will flood the engine through the exhaust valves. I think your model might have a siphon breaker but it may not. If the siphon breaker was plugged it could cause backflow. Unless the raw water impeller in your engine was worn out, I cannot see water under pressure getting through in quantity. The raw water intake is always under pressure in the water.

I am adopting my own protocol for running this new engine in my new boat. The raw water is off until the engine starts. I expect the first start may take some grinding to get fuel into the filters and engine. Not great on the impeller but I can dribble in a bit of water too.

I would suggest going through your wet exhaust system to check for a siphon blockage, as well as marginal design for the length of exhaust hose, muffler height, and storage capacity of the waterlock. The Vetus catalog offers design guidance and other sources do too.

I would agree you are lucky to save your engine when flooded. It is your worst nightmare. When sailing I always kept my raw water intake closed. Only when the engine needed to be run did I open it.

Good luck!

Montanan 08-04-2020 11:16

Re: Yanmar engine Seized in a sailboat
 
Quote:

Originally Posted by Thumbs Up (Post 3111911)
First you need to get all of the water out. Then you should change the oil. Then run it hot. Then change the oil again.

Yes if there is water coming out of the air intake and filter manifold then you have flooded the engine.

One must hand crank the engine slowly to push any water out of the pistons and through the valves; drain the oil so as to get as much water / oil emulsion out of the oil pan, replace the oil filter, then refill with oil, restart for a short period of time, just a few minutes at idle and no load so as to get the remaining water to emulsify with the new oil, then drain the oil and replace the filter yet again, then restart under a modest load when in the water [tied to the dock] so as to warm the engine, then drain and replace the filter yet again and top up with oil.

Oil and water don't mix and make for a terrible lubricant and if left in place for any length of time will result in internal corrosion.

Lesson learned: Do not do what you did ever again.

Thumbs Up 08-04-2020 11:45

Re: Yanmar engine Seized in a sailboat
 
Quote:

Originally Posted by gbowen (Post 3112111)
I think there is more to this. I had my boat on the hard for 5 years and ran the engine frequently with a garden hose in the raw water intake. It was a Yanmar 3QM model. That model came with a siphon breaker in the cooling water circuit. I am building another boat now with a new 2YM15 engine now installed. There was no siphon breaker in the cooling water elbow so I drilled and tapped and put one in. There is a sticker on the motor stating hydrolift mufflers can ruin your engine.

My old Yanmar would start first pop and the wet exhaust system worked great. I could check for cooling water flow by watching the small siphon outlet outside for dribbling.

There is grave danger if your motor cranks and the engine does not start for some reason. The wet exhaust system will overload with raw water and the water backflow and will flood the engine through the exhaust valves. I think your model might have a siphon breaker but it may not. If the siphon breaker was plugged it could cause backflow. Unless the raw water impeller in your engine was worn out, I cannot see water under pressure getting through in quantity. The raw water intake is always under pressure in the water.

I am adopting my own protocol for running this new engine in my new boat. The raw water is off until the engine starts. I expect the first start may take some grinding to get fuel into the filters and engine. Not great on the impeller but I can dribble in a bit of water too.

I would suggest going through your wet exhaust system to check for a siphon blockage, as well as marginal design for the length of exhaust hose, muffler height, and storage capacity of the waterlock. The Vetus catalog offers design guidance and other sources do too.

I would agree you are lucky to save your engine when flooded. It is your worst nightmare. When sailing I always kept my raw water intake closed. Only when the engine needed to be run did I open it.

Good luck!

Yes the siphon break is very important. In this case though he stated that he plumbed a garden hose directly to the raw water pump, then shut off the engine before shutting off the water which made for a very easy diagnosis.

mvweebles 08-04-2020 12:59

Re: Yanmar engine Seized in a sailboat
 
For future reference, some good pointers in a 2018 Steve d'Antonio article for Ocean Navigator. He has many articles on various exhaust topics on his website. He is such a prolific writer I swear there must be identical d'Antonio triplets all named Steve.

Exhaust system design - Ocean Navigator - May/June 2018

Thumbs Up 08-04-2020 13:21

Re: Yanmar engine Seized in a sailboat
 
Quote:

Originally Posted by mvweebles (Post 3112179)
For future reference, some good pointers in a 2018 Steve d'Antonio article for Ocean Navigator. He has many articles on various exhaust topics on his website. He is such a prolific writer I swear there must be identical d'Antonio triplets all named Steve.



Exhaust system design - Ocean Navigator - May/June 2018

He also recently became a cruiser forum member

paralog 08-04-2020 13:54

Re: Yanmar engine Seized in a sailboat
 
Quote:

Originally Posted by Montanan (Post 3112130)
Yes if there is water coming out of the air intake and filter manifold then you have flooded the engine.

One must hand crank the engine slowly to push any water out of the pistons and through the valves; drain the oil so as to get as much water / oil emulsion out of the oil pan, replace the oil filter, then refill with oil, restart for a short period of time, just a few minutes at idle and no load so as to get the remaining water to emulsify with the new oil, then drain the oil and replace the filter yet again, then restart under a modest load when in the water [tied to the dock] so as to warm the engine, then drain and replace the filter yet again and top up with oil.

Oil and water don't mix and make for a terrible lubricant and if left in place for any length of time will result in internal corrosion.

Lesson learned: Do not do what you did ever again.

I fried my Yanmar 3Gm with this issue, though I do believe the previous owner had done it as well as it was always terrible to start and just go worse over about 4 years. I was also told when replaceing the engine that the water lock was not low enough and this allowed water to back into the engine easily.
When i installed the new Beta we made sure the drop was correct.

Oceanride007 08-04-2020 14:47

Re: Yanmar engine Seized in a sailboat
 
So easily damaged isn't it, good thing it wasn,t sea water. Lets hope no lasting issues like glazed bearings, rings stuck in groove.
Someone suggested sucking out of a bucket, good but can achieve same thing by closing sea suction, taking off lid of sea suction strainer and top up with FW as when it is require when engine is running.
If such as your mistake happens, you have to purge it as much water as you can from cylinders and sump, by hand cranking, maybe flush with diesel overfilled hand cranked (Certainly for engine submerged in SW),wash it thoroughly in Diesel or kero), if leaving overnight you must get oil onto the liner surface, in a pinch you could try spraying WD40 or the like into the manifold as engine is turned. Ideally you have oil on hand and you keep working on it as suggested above, till you can get it running. Don't relax yet, in a few hours/days, your rings may still stick due to rapid corrosion on liner surface. Hand crank and lubricate, getting injectors out would be ideal to get spoon full of oil down each pot.


If a engine is submerged, I'd be worrying about fuel injection system as well. If its common rail :facepalm:.

sailcrazy 08-04-2020 19:03

Re: Yanmar engine Seized in a sailboat
 
Following. We hydro-locked our 4JH-TE-without knowing it. Ended up completely rebuilding the engine


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