Stanley, I have a 28hp BD1005, when I crank it it runs fine for approx 5 min the it will loose rpm's for a few seconds, and it might do this once or twice. The fuel system is clean, any suggestions?
How old is this engine? You dont say if this is a new problem and that the engine has just started this or if it has always done this. This has to be related to your fuel system. I suspect that you are sucking a little air from one of the following 1) a faulty seal on the primary fuel filter / water seperator 2) a hose clamp that is too large for the fuel hose and thus not round where it closed on the fuel line 3) the pick up in the tank may have a restriction or crack 4) the fuel tank breather may be partially blocked 5) the air filter may be blocked.
The engine is 2yrs old and has less than 100 hrs on it. I'm using the large Raycor top load filter. It just started doing this and it only does it for a few seconds during initial warm-up. New filters all around. Would an inline vacuum guage shed light on this?
The first place that I would look is the Racor. It is possible that you have the "O" ring seal under the top cover slightly pinched or the O ring seal around the T handle is not sealing perfectly. Either of these could cause your engines symptoms. Also check all the hose clamps on your fuel lines. One may have loosened up.
A vacuum gauge in the line will not help here. It can help by showing a blocked filter but when the system is clean there most likely will be very little or no vacuum showing on the gauge. I suspect that you have some air coming into the system so the gauge will still read zero.