Yanmar 3gm30f raw water hose routing

[coz]

Hey, does the Raw water intake with strainer need to stay below the intake pump? Yanmar 3gm30F. done everything and wondering if it is the placement or I need a new housing, ( 2000 hrs, 10 yrs old, fresh and salt).
thx COZ

[tkeithlu]

Nope. The only real difference is that the pump will stay permanently primed, which it may do in both cases, given that from your description the pump is below the waterline. Is the throughhull in a location that will not take it out of the water on a hard heel?

[coz]

Sorry, it's been a process. Raw water pickup is abaft the keel about 6" to port. It does get to overheating on a 1/4 reach or heavy seas. From other responses I have replaced the mixing elbow but I am still getting very low water flow from the pump. It turns out it is a Johnson pump xxxxx-02 and it should be the xxxxx-01 with a higher cam lobe. I cross referenced a pump for considerably less than the Johnson. It is the JPR-YM08iH for about $200. The impellers are expensive $50. So, I am probably going to swap this out and get back later. I just can't believe a reputable shop installed this (18 years ago) and no one can seem to recall replacing it......

[tkeithlu]

Do believe. At least it wasn't a half-axxed job that would sink your boat. Don't ignore the possibility that the low flow is from other sources, such as a partially clogged inlet.

[sagablu]

Check also that the hoses downstream of the pump are clear. Upon purchase of my new old boat, I found a couple pieces of an impeller within the hose. No indication from the outside that this was the case. Take a look also at the heat exchanger, make sure it's not calcified or otherwise clogged.

Good luck

[Gary Mc]

On my 2GM the raw water pump had a very poor flow rate. I rebuilt it with a kit, which was mainly new bearings and seals, and it worked much better. Not sure if that would apply here but just saying?

Good Luck

[Frankly]

Also be sure the pump is not installed backwards. Once during impelled replacement, I convinced myself that it would go back either way and probably still pump some amount of water. Never tried it but looked like easy trap to fall into.

Also once found my elbow just at the thru hull was almost completely blocked with some calcerficious deposit. Cleaned it out and good flow restored. "You always find the problem the last place you look ".


Frankly

[coz]

Originally Posted by Frankly

Also be sure the pump is not installed backwards. Once during impelled replacement, I convinced myself that it would go back either way and probably still pump some amount of water. Never tried it but looked like easy trap to fall into.

Also once found my elbow just at the thru hull was almost completely blocked with some calcerficious deposit. Cleaned it out and good flow restored. "You always find the problem the last place you look ".


Frankly

HAHA! I did exactly that a couple of months ago after replacing the shaft seal and impeller. I reassembled it on the bench, re-mounted it and it baffled me that the intake hose was at a slightlty different angle. I realized then that I had it rotated in the bracket and it would actually pull water out of the heat exchanger and blow it out the thru hull. I felt sloppy and dumb. I honestly believe that the smaller cam in the housing has worn and it is now time to replace with the proper pump housing. The 2mm cam worked for a few years but there is a lot of sand in our river and it could not put even 1gpm in a bucket at 2500 rpm. Thank you all for your help and I thank my stars I am in the ocean or at some faraway transient dock trying to figure this out. Just waiting for the new pump now.....
COZ