All the suggestions thus far are valid,
1 drain down the coolant level,
2 scrupulously clean the top of the cylinder head of dirt and debris especially the copper cup that the injectors are recessed into.
3 pour a very small quantity of WD 40, liquid wrench, or other suitable penetrating
oil product into the copper cups and leave for 24 hours
4 while this soak it happening. Focus on the point that while the engine is
Volvo Penta, The entire
fuel system is BOSCH. This will save you a lot of
money. find A Bosch dealer and ask for an old union nut that is identical to the one that holds the
fuel line on. This can then be used to make a slide hammer puller. Buy or acquire a 8 inch long 1/2 diameter bolt. Drill and tap a hole in the end of it. So that a screw can be passed through the union nut and the head will loosely retain it there on the end of the bolt. You will also need a heavy weight with a half inch hole through it to slide on the bolt.
5 disconnect the lines and the clamps...and attach your home made slide hammer to the thread on the end of the injector. Drawing the weight up with a slight slamming action against the head of the bolt should extract the injectors without affecting the press fit of the copper cups.
6 have the injectors rebuilt by the Bosch authorised service centre.
7 replace injectors using the
seals the service centre will invariably provide and put never seize grease on the bottom end of the injector before inserting. the spare union nut can be placed on the top of the injector and tapper with a soft mallet.
8 replace clamps and fuel lines.
Final suggestion fit a suredrive made by 'Next wave
marine systems inc' of Qualicum Beach
Canada into the flywheel/ bell housing of your engine. To protect your 20 tooth drive spline from shearing. This joint between the engine and
transmission is known for failure. of course if you have already sheared it then you really need to call them as they ship to anywhere in the world. and since that requires no modification machining whatsoever you can install it with the simple tools provided and be on your way immediately.