So I spent a week polishing the old girl in some of the hottest weather this summer and decided to take her out for a quick spin.
Started off fine but slowly it became apparent she wasn't running quite right,nothing you could put your finger on but she seemed down on power and a hill I usually fly up called for a gear change.
She seems to have lost her edge,I have a fuel filter system fitted which has a clear glass sediment bowl which is clean but I noticed quite a few air bubbles in it if I give her some throttle,could this be the problem?I have the cummins engine which has been pretty good up until now but I guess like plenty of others who bought their buses 10 years ago or more little things are starting to play up which is where I find this site so invaluable for the help that those in the know impart to other owners .
Keep up the good work

Graham

My bus number (if any): rml2478

You could check that the fuel feed lines and joints are all sound from the tank to the fuel filter as the hot weather may have caused any flexible ones to become more supple so that they let in a bit of air or partial collapse internally restricting fuel flow under load ? If air is getting in I would have thought starting would be an issue as the fuel would drop back from the pump while turned off ? Obviously you could change the fuel filter and water trap filter if they haven't been changed as diesel doesn't have a very long shelf life now, we find performance issues are often sorted by a filter service.

My bus number (if any): RML2747

Hi Graham
I recently changed all filters Air,Fuel and oil so I don't think it's a filter problem I even cleaned out the filter in the lift pump as that has given problems in the past.
She fires up really quickly so no reason to think fuel is running back while stood.
I'm tempted to run a temporary fuel line just to check see if that works.

Graham

My bus number (if any): rml2478

Check for air leaks on the throttle dip valve if yours is still fitted with one, that can cause loss of power not giving full throttle. Wear and tear/excess play on throttle linkage ball joints?

Wearing sandals instead of heavy winter boots?? :)

My bus number (if any): RML2532

Graham has the problem occurred since you changed the filters ? If so are they all fitted tight enough or perhaps some sediment got disturbed and had found it's way in to the system - if you have a water seperator filter have you drained any water from the bottom of it ?

My bus number (if any): RML2747

My bus number (if any): RM967 (Driver/Restoration consultant)

Hi Graham

I had a similar problem with 548 (cummins B series) in 2014, problem turned out to be a faulty lift pump.

David

My bus number (if any): RM's 765, 548, 1783 and 446

Graham B yes the problem has developed since I changed filters but she has done about 500 miles since i did.I haven't drained any water from the seperator filter recently in fact I don't think I have ever drained it.I guess the guy who services it does but can't be sure.
Graham L I'm going to check flywheel oil level to morrow'it sounds like a possibility to me.
David L I,ve checked the lift pump as best I can and it seems to be really pushing the fuel through quite well.
After dirty fuel problems 2 years ago I am now a dab hand at getting the lift pump apart and cleaned out properly,I wonder how many other owners know about the little filter in the pump?
Thanks gentlemen I'll keep you posted as to what it turns out to be.

Graham

My bus number (if any): rml2478