A few notes to add to perhaps another video. The inlet hose usually comes from a raw water strainer which is a daily check before operating the boat, and it catches any plants/algie (even small fish that make it through the thru-hole-valve. Secondly, on both hoses two clamps is the prefered method of installation. Lastly, I recently completely rebuilt from scratch my 3GMF engine on my boat, which is the 22 hp version of the 3GM30F engine (slighly larrger piston displacement, otherwise the same engine internally and externally, and actually replaced the 3GMF in second half of the 80's). I replaced several external components with new ones, and saved the removed companents (starter, alternator, cooling pump, secondary fuel filter, fuel injectors) as spares, including the raw water pump. I keep the spare completely rebuilt including the flat bracket, and when service time comes, I simply replace the entire turn key pump assy, and rebuild and store the removed one to be the new spare. Saves times and if I find myself with a clogged pump, or faulty impeller, I have one handy ready to go in. Another tinng is the rear cover. If anything foreign goes in the pump past the strainer, the inside of the cover gets scored. This does not produce a leak, but because the impetter clearances are increased, the pump becomes inefficient, which is another reason why I even keep an extra cover handy, along with two or three impellers and gaskets. Cheap insurance. Tough to sail several hundred miles, and finding out the engine overheats when trying to motor to a marina, and finding out, no spare parts are readily avilable.

Crystal clear. Thank you so much! You are a superb instructor!

Outstanding and so clearly explained. I am just about to change the impeller on my GM 30 F Yanmar. I needed to see this. Thank you! ⛵️

Thank you for the great, clearly and thoroughly explained videos!!

ONE OF THE BEST AND MOST COMPREHENSIVE VIDEO IVE SEEN.... MY IMPELLER IS A DIFFERENT DESIGN WITH NO BAR BUT EVERYTHING ELSE IS AS YOU DESCRIBED... GREAT JOB..... I WOULD LIKE TO SEE A VIDEO ON FUEL FILTER CHANGES BY YOU IF YOU HAVE ONE

It's always nice to meet somebody with the same engine, somebody with the stupid courage to post videos, too, ha ha. I love your mechanistic explanations. You made the correct decision not to use the paper gasket, a rubber O ring is always incompatible with paper gaskets. Both are provided, for those who prefer a paper gasket by itself. O rings offer a better seal, and they are easier to replace. If possible in your system, you might want to prefill the intake line with water, so on startup the impeller vanes don't overheat from lack of lubrication when it tries to burp the trapped air. By the way, what are those two filters, attached with blue fittings to the left of the screen at 8:54? Are they water filters for your tap water?

thank you for the video explanation

Thanks for showing you turn the water valve off……..

Overall a very good video thank you for your depiction however the note should be added about putting the antifreeze back in before you crank the engine

Speedseal would make the impeller change a lot quicker. There are four bolts in total that are loosened and tightened with locking pliers. Only two bolts need to be removed so a cover could be removed. I use angled long nose pliers in order to pull out an impeller. It takes some practice but once you've done few times, the whole job shouldn't take more than 15 minutes. Takes a bit longer in rough seas as I had the joy to find out 😉.

Great job! The manual was not helpful. I can do this now!

what size socket did you need??

I noticed that the blades on the new impeller were bent in the opposite direction as the one that you removed. Did that turn out to be a problem? Great video. 👍

That is not a Yanmar salt water pump and impeller. Cannot believe how clean and rust free is your engine.

That pump and the alternator are not original from the factory( they should be same colour as the engine), why did you changed them?

I like the color of your hat but the flapping halyard is annoying.

Sorry but he missed (in fact got wrong!) The most important fact that you haveto get the rotation of the impeller THE RIGHT WAY AROUND!