Crank-mounted water pump?
#13
BEACH PARTY / HOLLOWPOINT
Platinum Member
Thread Starter
Johnson F6B-9 is the one I’m going to order. It’s supposed to be as good as if not better than the Merc pump. Ordering today and will also look into spacer plates that I can modify for the mounting.
On another forum, a solution was to machine some stand-off bushings to align the pump and also lessen them depth (the serpentine pulley too deep).
On another forum, a solution was to machine some stand-off bushings to align the pump and also lessen them depth (the serpentine pulley too deep).
Last edited by TomZ; 10-03-2021 at 11:50 AM.
The following 2 users liked this post by Rookie:
articfriends (02-16-2022), TomZ (10-04-2021)
#16
BEACH PARTY / HOLLOWPOINT
Platinum Member
Thread Starter
Specs on the pump state max rpm of 5k. Any concerns running them upwards of 6k?
Another note... be on the lookout for knock-offs. Lots of junk out on Amazon, eBay, etc.
Another note... be on the lookout for knock-offs. Lots of junk out on Amazon, eBay, etc.
#18
Registered
I run those pumps and have run them over 6k without incident. Do pump a bunch of water though! I switched headers that had a small hole to exhaust water and blew the freeze plugs out of one motor! Had to overboard the excess water (and install pressure gauges). Simple, efficient and if you have room, a fairly easy impeller swap. (I use 90* needle nose, but they actually make a little tool to reach in and slide the impeller out)
The following users liked this post:
TomZ (10-04-2021)
#19
BEACH PARTY / HOLLOWPOINT
Platinum Member
Thread Starter
I run those pumps and have run them over 6k without incident. Do pump a bunch of water though! I switched headers that had a small hole to exhaust water and blew the freeze plugs out of one motor! Had to overboard the excess water (and install pressure gauges). Simple, efficient and if you have room, a fairly easy impeller swap. (I use 90* needle nose, but they actually make a little tool to reach in and slide the impeller out)
I'd imagine this is especially important on a Gen VI block where the water jacket to side of the block surface is thin. My 502s seeped at the head/block joint due to high water pressure. It'll no longer be an issue with closed cooling but it was a big problem when raw water cooled and at speed.
#20
BEACH PARTY / HOLLOWPOINT
Platinum Member
Thread Starter
Found this on the Formula Boats forum... good list of parts.
How-to: convert your Merc raw water pump to crank-driven Johnson (take 3))
How-to: convert your Merc raw water pump to crank-driven Johnson (take 3))