Larson 290

[SteveGroves]

Last weekend, a friend and myself set out to swap a knackered waterpump (the one on the front of his engine, with the drive belt on it, not the pump in the leg) on his larson 290, with 4.3L Mercruiser engines, but failed dismally at the first hurdle cos even after practically dismantling the boat we couldnt find any seacocks or strainers and neither of us fancied cracking the seal on the pump without first knowing the water was going to stay on the outside of the hull!
Can anyone shed any light on whereabouts the seacocks and strainers are on this boat?

Steve

 

[Chris_d]

Last weekend, a friend and myself set out to swap a knackered waterpump (the one on the front of his engine, with the drive belt on it, not the pump in the leg) on his larson 290, with 4.3L Mercruiser engines, but failed dismally at the first hurdle cos even after practically dismantling the boat we couldnt find any seacocks or strainers and neither of us fancied cracking the seal on the pump without first knowing the water was going to stay on the outside of the hull!
Can anyone shed any light on whereabouts the seacocks and strainers are on this boat?

Steve

Outdrives engines don't have seacocks normaly, the strainer would be on top of the engine generaly. Best thing to do is remove the inlet pipe and keep it held up above the waterline, if you can bend it over or blank it with a cork or something that will stop water coming in

 

[spannerman]

If its an Alpha leg then the pump is in the drive and the seawater inlet hose comes in at the thermostat housing so its not going to flood the boat as the pump will block the flow and the hose will most likely be above the waterline at the t/stat housing.
If its a Bravo leg then the pump is mounted low down on the starboard side of the engine and again delivers water up to he t/stat housing so it won't flood for the same reasons.
You can remove the circulation pump safely, I would drain the block down first by means of one of the drain cocks, one each side of the block low down half way along just aft of the engine mounts, usually a brass plug 9/16" socket if I remember, you may have to stick a screwdriver in the hole to shift any rust which accumulates to get it to drain. I would drain via the port plug to prevent seawater splashing over the starter motor.
I trust you have bought an original pump or at least a Marine version, as fitting a car type GM block water pump will not last long with seawater in it.
And there are no strainers on a standard Mercruiser V6.

 

[SteveGroves]

Mercruiser re-circulating pump

Cheers Steve,
Thanks for your help, I'll let you know whether or not we manage to change the pump, without sinking the boat after the weekend! (and he's bought it form Keyparts so it should be a proper one!) As I commited shaft drive boater, the concept of not having weed filters is a bit alien, I must admit, I dont understand how you keep weed/fishing line/general cr*p out of the engines without filters, but it makes sense as we combed the engine bay for something that looked like strainers.

Steve