MEP-831a Not Starting

[36racin]

Recently purchased a 831. Charged battery. Unit cranks over but appears there is little or no compression. It appears fuel is coming out the side of the head. Thru this space(see pic) just in front of the exhaust manifold bolting studs. I was thinking it is a blown head gasket? Previous owner changed oil. Filled thru top of valve cover. Tried to restart and it blew oil everywhere he said. Hasn’t started since then. Can videos be posted here. I can’t figure it out if it can. I added a youtube link with a video...Just the first 8 to 10 seconds of the video show the issue...

- YouTube

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Todd

 

[36racin]

Recently purchased a 831. Charged battery. Unit cranks over but appears there is little or no compression. It appears fuel is coming out the side of the head. Thru this space(see pic) just in front of the exhaust manifold bolting studs. I was thinking it is a blown head gasket? Previous owner changed oil. Filled thru top of valve cover. Tried to restart and it blew oil everywhere he said. Hasn’t started since then. Can videos be posted here. I can’t figure it out if it can. I added a youtube link with a video...Just the first 8 to 10 seconds of the video show the issue...

- YouTube

Enjoy the videos and music you love, upload original content, and share it all with friends, family, and the world on YouTube.

www.youtube.com

Todd

Doen't appear to be head gasket....The unit came with a gasket kit so I replace the head gasket. Still blowing fuel/combustion out the side as shown in video. Now Im thinking the head is cracked where I cannot see it inside that area.....Or I did find the injector bolts loose...maybe the injector orings are blown...Ima look thru the TM's to see what they look like and torque specs on them.

 

[2Pbfeet]

Well, it could be a cracked head, but I am curious what the head looked like when you had it off.

I would check a few things before getting to the conclusion of a cracked head.

Is the decompression lever and spring working? How does the rocker arm for the exhaust valve look, specifically where it would make contact with the decompression lever.

I do wonder if there is a story behind the corrosion inside the exhaust port. To me, it is an odd place to get wet, and if there was water in the exhaust port to that height, I would have concerns about somebody perhaps cranking a hydrolocked engine. Have you checked the valve clearances, and that the tappet rods are straight and not bent?

I don't quite understand what the previous owner did. Normally, there shouldn't be oil spraying out, unless the prior owner forgot to screw the lid back on, or dumped oil around the head area generally, and even then the oil drains down pretty quickly, but not instantly, so there is certainly the potential to damage things and/or overfill the engine. Did the owner overfill the oil? Have you changed the oil, and check the level?

All the best,

2Pbfeet

 

[36racin]

Well, it could be a cracked head, but I am curious what the head looked like when you had it off.

I would check a few things before getting to the conclusion of a cracked head.

Is the decompression lever and spring working? How does the rocker arm for the exhaust valve look, specifically where it would make contact with the decompression lever.

I do wonder if there is a story behind the corrosion inside the exhaust port. To me, it is an odd place to get wet, and if there was water in the exhaust port to that height, I would have concerns about somebody perhaps cranking a hydrolocked engine. Have you checked the valve clearances, and that the tappet rods are straight and not bent?

I don't quite understand what the previous owner did. Normally, there shouldn't be oil spraying out, unless the prior owner forgot to screw the lid back on, or dumped oil around the head area generally, and even then the oil drains down pretty quickly, but not instantly, so there is certainly the potential to damage things and/or overfill the engine. Did the owner overfill the oil? Have you changed the oil, and check the level?

All the best,

2Pbfeet

Thanks for the response....Decompression lever works as it should...Rocker arms look good, no wear. inside of head looked great...no carbon..no appearent cracks or wear...

I am now leaning towards a not seated properly fuel injector. I found both nuts completely loose. I tightened some but dont want to over do it until i read the TM somemore. Got injector out, washer out but will need to get seal out....Just going to go ahead and purchase a new seal.

My friend I purchased from isnt too mechanically inclined....He may have inadvertently loosened the injector not knowing trying to figure out why it would not start all of a sudden...I checked oil....its new and full as it should be....I will service the whole unit once I get it running again...

Best place to get parts for the Yanmar L-70 engine...OEM preferred.... The aftermarket head gasket was way thinner than the OEM one....


Thanks again,
Todd

 

[2Pbfeet]

Thanks for the response....Decompression lever works as it should...Rocker arms look good, no wear. inside of head looked great...no carbon..no appearent cracks or wear...

I am now leaning towards a not seated properly fuel injector. I found both nuts completely loose. I tightened some but dont want to over do it until i read the TM somemore. Got injector out, washer out but will need to get seal out....Just going to go ahead and purchase a new seal.

My friend I purchased from isnt too mechanically inclined....He may have inadvertently loosened the injector not knowing trying to figure out why it would not start all of a sudden...I checked oil....its new and full as it should be....I will service the whole unit once I get it running again...

Best place to get parts for the Yanmar L-70 engine...OEM preferred.... The aftermarket head gasket was way thinner than the OEM one....


Thanks again,
Todd

Yup, a loose injector will definitely cause low compression. Do read the TM about washers and torque; that's an aluminum casting.

All the best,

2Pbfeet

 

[36racin]

Yup, a loose injector will definitely cause low compression. Do read the TM about washers and torque; that's an aluminum casting.

All the best,

2Pbfeet

Yep loose injector it was....Reinstalled and cranked and it kicked off....Now I'm not getting fuel. Have fuel from tank all the way to the injection fuel pump...But nothing out of the pump...On to the next problem....

 

[2Pbfeet]

Yep loose injector it was....Reinstalled and cranked and it kicked off....Now I'm not getting fuel. Have fuel from tank all the way to the injection fuel pump...But nothing out of the pump...On to the next problem....

Again, the TM is your friend, but a few questions;
does the governor lever move when you go to start / stop it?
If yes, then I would clean the area below the pump where there is a triangular-ish plate held on by one nut. Remove the nut and plate, being careful not to let any dirt drop in. Check to see if the pin is in the yoke, and moves when the governor control is moved.

Comment: I keep a few known good pumps around to make troubleshooting easy on these engines, and at least one known good injector.

All the best,

2Pbfeet

 

[36racin]

Again, the TM is your friend, but a few questions;
does the governor lever move when you go to start / stop it?
If yes, then I would clean the area below the pump where there is a triangular-ish plate held on by one nut. Remove the nut and plate, being careful not to let any dirt drop in. Check to see if the pin is in the yoke, and moves when the governor control is moved.

Comment: I keep a few known good pumps around to make troubleshooting easy on these engines, and at least one known good injector.

All the best,

2Pbfeet

Worked my way thru the no fuel issue...Pulled injection pump and appears the plunger was stuck...cleaned and lubed it and all is good now. Unit started and was running smooth and making power. And its charging the battery. Let run to burn off the oil inside/outside the muffler as the smoke got heavy for alittle while. About 15 minutes of runtime the governor started swinging randomly. I'll have to get a video of it and post....Also the courtesy plug started tripping a heat fuse inside the machine under the cover. Nothing major. Machine hasnt operated for 5 plus years so I know I'll have to work thru issues.

Had to replace the vent line off the injector as it was dry rot and leaking somewhat.

Where can I get a quality injector and pump....I probably should keep one on hand

Thank you for the assistance...

Todd

 

[2Pbfeet]

Worked my way thru the no fuel issue...Pulled injection pump and appears the plunger was stuck...cleaned and lubed it and all is good now. Unit started and was running smooth and making power. And its charging the battery. Let run to burn off the oil inside/outside the muffler as the smoke got heavy for alittle while. About 15 minutes of runtime the governor started swinging randomly. I'll have to get a video of it and post....Also the courtesy plug started tripping a heat fuse inside the machine under the cover. Nothing major. Machine hasnt operated for 5 plus years so I know I'll have to work thru issues.

Had to replace the vent line off the injector as it was dry rot and leaking somewhat.

Where can I get a quality injector and pump....I probably should keep one on hand

Thank you for the assistance...

Todd

Congratulations on making progress!

Commonly an air leak will generate the hunting behavior that you describe. If the vent line was in trouble, there may be other hoses that are just old and start to leak as the engine area warms up. I would also double check the high pressure line fittings after the initial warm up and loading.

A local marine Yanmar dealer probably has L70 injectors in stock. In a pinch, many of the big online vendors (Amazon, eBay, etc.) have clone pumps and injectors, injectors, and occasionally the latter has NOS Yanmar pumps and injectors.

All the best,

2Pbfeet