Yanmar Fuel Supply Problem

[Rezzy]

Yanmar 4JH5E

This is a new engine with just 200 hours and runs very sweetly. It always starts – eventually – but demonstrates this fault. Under warranty but not near a dealer.

Sometimes starts first time but other times it takes four to seven presses of the button. Each time it does start but dies seconds after until the fourth or so time when it fires and runs normally.

A couple of times the warm engine has just stopped when idle and then restarted when the button is pressed but this problem is rare.

So, obviously this is a fuel issue but what kind? Checks so far: All fuel hoses are tight, the idle setting is at 800rpm as normal, engines runs well so fuel is okay, engine self bleeding for possible air. No rough running whatsoever.

Haven’t yet changed the fuel filter but it’s a new engine? So guys, what do you think?

Thanks in advance, Rezzy.

[Lepke]

You probably have air entering the fuel lines somewhere. It's a lot easier for a pump to draw air than fuel. If the engine runs well under load then it's probably a very small leak. Several start attempts is often air in the injector lines. The air compresses each start try until enough fuel displaces the air. Injectors usually have some sort of spring controlled check valve. When the air compresses, the pressure drops below the spring tension and little or no fuel is discharged.
Next time try bleeding the injector tubes before starting. Crack open the nuts until fuel flows freely. Use rags to catch the fuel. If it solves the problem or helps, then you've confirmed you have an air leak.

[PamlicoTraveler]

Originally Posted by Rezzy

Yanmar 4JH5E

This is a new engine with just 200 hours and runs very sweetly. It always starts – eventually – but demonstrates this fault. Under warranty but not near a dealer.

Sometimes starts first time but other times it takes four to seven presses of the button. Each time it does start but dies seconds after until the fourth or so time when it fires and runs normally.

A couple of times the warm engine has just stopped when idle and then restarted when the button is pressed but this problem is rare.

So, obviously this is a fuel issue but what kind? Checks so far: All fuel hoses are tight, the idle setting is at 800rpm as normal, engines runs well so fuel is okay, engine self bleeding for possible air. No rough running whatsoever.

Haven’t yet changed the fuel filter but it’s a new engine? So guys, what do you think?

Thanks in advance, Rezzy.

As far as I'm concerned, if a diesel doesn't start right away, there is a problem. It sounds fuel related, but may be something else with all of the electronic fuel pumps etc. 200 hours is certainly not too early to change the filters, primary and secondary (on the engine, probably 2mm). I would start there, and maybe you will find gunk in the filters.

[feebs]

Had a similar problem with my 3JH5E. See thread started in 26/1/18. (Would post link... but don’t know how!)

Anyway, after checking for water in fuel, changing filters and fuel lines, it looks to be a loose banjo fitting on primary filter which caused this problem. Tightened & hasn’t happened since. Fingers crossed it was that simple...

[Wotname]

^^
Here you go
http://www.cruisersforum.com/forums/...se-196592.html

[Terra Nova]

Install electric fuel pump. Check for leaks.