Long start period Diesel motor

[branko]

I have install new diesel generator. Fuel is from main diesel tank ( Bottom of the motor!!). When diesel gen is cold it needs approx. 25 seconds rotating to start.It looks that fuel goes back in tank during stop period and need time to surge it again from tank.
I am thinking to involve Check valve in suction diesel tube near tank to obtain that suction tube is allways full with fuel. Any suggestions?

 

[macd]

I'm just in the process of fitting a new Beta engine. The installation guide stresses that the fuel return pipe should loop to a lower level than the filter/separator, then back up above it, otherwise you can get 'drain down' and poor starting. Seems that this might fit your situation.

 

[paddywackcocker]

If you are getting fuel run back to the tank, then air must be entering the system. As you say the instalation is new I doudt it would be the lift pump. Most likely candidate would be a connection, pipe to union or union to fitting. Is the pick up and delivery pipe new. One way valve would work but would introduce a restriction and would be prone to blockage and may not allow suficent fuel for high loading of genny. You could introduce a electronic fuel shut off valve. I think I would look for entry of air first.
If the tank is very low down and you have long periods off non use, then makeing sure the diesel leekoff/return is submersed in the tank then this should exclude any possebility off run back

 

[branko]

Thanks for advise.It could be the reason as I do not install filter separator and fuel tubes ( in and out) lies at the bottom on same level. I shell check all connectors also for air leaks in! I shell also install fuel separator and lift up return tube between fuel separator and tank.

 

[Guest]

Sounds like air getting into line somewhere and line siphoning back. If its a trait unsolvable by relocating pipe run / remaking joints etc. - then install a valve in the fuel line with a notice at the start point to open valve when you want fuel ....
It is not unknown for a seemingly good installation to drain back for some apparent but hard to find reason.