must have a really big impeller so it's no wonder it's a fight. My little puny 4-108 impeller can be pinched with my fingers. I slop it up with grease and rotate my hand while pushing against the pump and it slips right in. The one thing I have going for me is that the pump is right at the front of the engine easy to get at. I can kneel right down in front and do all my engine work with no trouble. I can have the pump off in no time. Actually, I have it pretty easy on the generator as well. The hardest thing to work on in the entire engine compartment was the packing gland and now that it's been modified it's a snap as well. The mechanics should be paying me to work on my engine it's so easy!