mpmiller101
New Member
Does anyone know how to tell these two engines apart? My Macwester 22 came with one of these which has, until very recently, been easy to start and and has run perfectly. The original engine had a fuel tank above and various metal protective covers which might have had a logo indicating whether it was a PMX 6 or 8, but mine has no obvious label.
I have the operators manual and the service manual which are common to both engines. The latter has beautiful parts diagrams showing all components (apart from the interior working of the dynastart). (By the way, if anyone wants a copy of the service manual send me a personal message and I can email the pdf file. I came across it accidentally on a Dutch website but have lost the address.)
The only difference I can find in the diagrams between the two engines is a difference in shape of the lower part (ie the side towards the engine) of the fuel injector. Based on this I think I may have a PMX 6. Does anyone know if this is absolutely diagnostic or is there another way to tell by external examination?
In the last few weeks the engine has become very difficult to start and also it won't idle at as low a speed as it used to. At low speed it tends to "search about" a little (ie not run at a steady speed) and is prone to cutting out. I've put in a new fuel filter and cleaned the tank, fuel lines, and the fuel injector and also adjusted the tappets. There was sludge in the tank indicating "the bug." On turning the engine by battery the injector give a nice conical well atomized spray of fuel, but on turning it by hand through the flywheel just a dribble comes out. The engine is still hard to start without using "Easy Start" spray but when running it now idles a little better but not as well as it used to. At higher speed it runs as it has always done and has plenty of power. The exhaust looks normal.
Is it possible that the fuel pump functions efficiently at high speed but is less efficient at low speeds. In the past when I've bled the fuel system I've done it by turning the flywheel by had and heard a distinct "bitz bitz" sound when the fuel got through the injector. This I can't hear now when turning by hand. Any suggestions?
My next step is to pull the fuel pump and see if there is any dirt or sticking parts.
Could carbon build up or a poorly seated valve be the cause of this problem? I want take off the head and lap the valves as it is well past the service interval. For this I need a head gasket - which brings me back to the original question - what engine do I have? (or, sacrilege, is it possible to reuse the same head gasket?)
Looking at the engine and the parts diagram I see no sign of any type of valve stem oil seal. Is this because of the horizontal cylinder or am I missing something?
I've been at this for days. The engine is awkward of access, my head is spinning with solvents and petrochemicals, I'm bumped, bruised, scraped, blackened and frustrated, and in order to use the Easy Start spray I have to push the starter button with my toe at full stretch.
Any help which saves me having to adopt these ridiculous unseamanlike postures will be most appreciated. Thanks in advance.
I have the operators manual and the service manual which are common to both engines. The latter has beautiful parts diagrams showing all components (apart from the interior working of the dynastart). (By the way, if anyone wants a copy of the service manual send me a personal message and I can email the pdf file. I came across it accidentally on a Dutch website but have lost the address.)
The only difference I can find in the diagrams between the two engines is a difference in shape of the lower part (ie the side towards the engine) of the fuel injector. Based on this I think I may have a PMX 6. Does anyone know if this is absolutely diagnostic or is there another way to tell by external examination?
In the last few weeks the engine has become very difficult to start and also it won't idle at as low a speed as it used to. At low speed it tends to "search about" a little (ie not run at a steady speed) and is prone to cutting out. I've put in a new fuel filter and cleaned the tank, fuel lines, and the fuel injector and also adjusted the tappets. There was sludge in the tank indicating "the bug." On turning the engine by battery the injector give a nice conical well atomized spray of fuel, but on turning it by hand through the flywheel just a dribble comes out. The engine is still hard to start without using "Easy Start" spray but when running it now idles a little better but not as well as it used to. At higher speed it runs as it has always done and has plenty of power. The exhaust looks normal.
Is it possible that the fuel pump functions efficiently at high speed but is less efficient at low speeds. In the past when I've bled the fuel system I've done it by turning the flywheel by had and heard a distinct "bitz bitz" sound when the fuel got through the injector. This I can't hear now when turning by hand. Any suggestions?
My next step is to pull the fuel pump and see if there is any dirt or sticking parts.
Could carbon build up or a poorly seated valve be the cause of this problem? I want take off the head and lap the valves as it is well past the service interval. For this I need a head gasket - which brings me back to the original question - what engine do I have? (or, sacrilege, is it possible to reuse the same head gasket?)
Looking at the engine and the parts diagram I see no sign of any type of valve stem oil seal. Is this because of the horizontal cylinder or am I missing something?
I've been at this for days. The engine is awkward of access, my head is spinning with solvents and petrochemicals, I'm bumped, bruised, scraped, blackened and frustrated, and in order to use the Easy Start spray I have to push the starter button with my toe at full stretch.
Any help which saves me having to adopt these ridiculous unseamanlike postures will be most appreciated. Thanks in advance.
