MEP-531AE-DEG Starting Issues

[hoodooed]

Bought this unit at auction. Was said to run and make make power. I changed oil, new fuel, new hoses, bled air and no start. I took out the injector and fliped it over to see the spray pattern. It looked good. Four distinct atomized sprays. It has compression, i have not gauged it but it feels right. Alot easyer to pull with compression release so i think compression is good. Checked valve lash and set to .006 Still no start. Im running out of ideas. The unit does not apear to have been taken apart other than the nato slave plug was removed. It is really clean looking. maybe timing? hope its something easy that im missing. Thanks in advance for the help.

 

[glassk]

Check that fuel tank has fuel and that fuel shutoff valve (Figure 3) located on the filter is positioned to
¯O
(open).

 

[DieselGenAC]

It should be almost impossible to pull through a compression stroke without pushing the decomp lever. Try starting it with the onboard electric starter. 12V is probably enough to start a 531A even with the 24V starter.

 

[hoodooed]

Thanks for the replies. I did put 12v to the starter and it cranks fine but still no start.

 

[DieselGenAC]

If you can pull it through a compression stroke with the rope starter, the engine has mechanical issues.

 

[hoodooed]

This is my first diesel gen, so i am no expert for sure, but would'nt you have to pull through a compression cycle in order for it to start? Am i missing something? Some yanmar L48's are sold with just the rope and no electric starter.

 

[DieselGenAC]

To rope start an L series Yanmar, you have to push the decompression lever to build some speed in the flywheel. Inertia carries it through the first compression stroke. The electric starter has enough torque to power through compression.

 

[hoodooed]

OK that makes sense Dieselgen. When I check the compression, I would pull the injector correct? Do you know what compression range I should be looking for? I can't come up with that number in any on line manuals. Thanks again.

 

[1800 Diesel]

Before you remove the injector, try getting an ounce or two of 15/40 oil into the cylinder via the intake manifold. Spin it several turns with the compression release down to get the oil well distributed in the bore, then try starting as per normal start using the electric starter. If that doesn't get it started then you may have valve seat leakage. If it does start you have rings or bore issues.

Not ruling out timing but at least try the oil thing 1st.

 

[rustystud]

OK that makes sense Dieselgen. When I check the compression, I would pull the injector correct? Do you know what compression range I should be looking for? I can't come up with that number in any on line manuals. Thanks again.

These smaller diesel engines still have a 21:1 compression ratio. Some have a 22:1 ratio. That's why the all come with decompression systems.

 

[RIrvin]

Following up on 1800 Diesel's suggestion, there should be a rubber cap covered port on top of cylinder head to introduce drops of oil into cylinder. Here is photo of mine . Port is labeled "B" in photo.

 

[hoodooed]

All good advice. I will try the oil on the piston today and report back. I do have the rubber covered port just like yours. Thanks again.

 

[R Racing]

I have had 5 of these and to get them fired up the first time after they have been drained, and all new fluids are in. I give them a shot of ether . it could have air in the fuel system still. or it could have a broken ring and be down in compression.

 

[hoodooed]

OK I am pretty sure that I have got bad news. I tried oil through the rubber port on top of the valve cover, no luck. Pulled the injector and dribbled oil on top of the piston while rotating the engine with pull rope hoping to get a good seal on the rings. No luck. This is what i saw. As I rotate the engine with the valve cover off, I have a gush of air coming out of the pushrod galley. Not good right?

 

[R Racing]

No I have that with mep831a I believe mine has a broken ring. I'm planning to take mine apart in the next month or 2 and rebuild it .

 

[1800 Diesel]

OK I am pretty sure that I have got bad news. I tried oil through the rubber port on top of the valve cover, no luck. Pulled the injector and dribbled oil on top of the piston while rotating the engine with pull rope hoping to get a good seal on the rings. No luck. This is what i saw. As I rotate the engine with the valve cover off, I have a gush of air coming out of the pushrod galley. Not good right?

Sounds like blow-by...before raising the white flag & while you have the injector out, I would pour a cup of Marvel oil on top of the piston & let it soak at least a week. You might get lucky if the rings got stuck at the same time the temperature was very cold. Just a theory here but if the rings were just slightly "collapsed " in the lands due to a hard freeze & that's when they happened to get stuck, you'd end up with low compression. Or the other possibility--the engine was run with low oil level & the bore got scuffed.

 

[hoodooed]

I just did some reading on marvel. Interesting. I had never heard about it before. I guess its worth a shot. OK, now for some opinions. There is a chance that I can get my money back from the seller. He says that he stands behind his sales. So....... I bought this genny for $350.00 and thought I got a deal. So..... did I get a good enough deal to do the rebuild, or should I get some money back? I have two gassers but kind of wanted the diesel. Almost all my other equipment is diesel. Let me know what yall think. Thanks again.

 

[R Racing]

I sold 1 of mine to a guy in construction for $750.00. He came back next week wanting to buy another . But I didn't want to sell it at the time because it was the last 1 I had. Then I bought 3 more lol

 

[rustystud]

I just did some reading on marvel. Interesting. I had never heard about it before. I guess its worth a shot. OK, now for some opinions. There is a chance that I can get my money back from the seller. He says that he stands behind his sales. So....... I bought this genny for $350.00 and thought I got a deal. So..... did I get a good enough deal to do the rebuild, or should I get some money back? I have two gassers but kind of wanted the diesel. Almost all my other equipment is diesel. Let me know what yall think. Thanks again.

It's a hard call to make. If it only needs rings then keep it, but if it needs much more then I would get my money back and try for a better one. Engine parts can really rack-up money fast !

 

[90cummins]

Yanmars are very good engines but don't use ether it will cause damage most likely breaking a piston ring land.
I have rebuilt 2 of these L70's that were wet stacked and the camshaft & lifters were damaged from corrosion which pitted the cam & lifters making them unusable.
You need to tear it down and evaluate it.
I would suggest Purple Power (Walmart) to clean the parts.
This is the best low cost cleaner I have found.
The minimum I would suggest for parts would be rings, rod bearing and a gasket set & seals. If it's really bad it will may also need a camshaft & all 3 lifters.
This can be done for under $500 including a new piston.
90cummins