Running engine ashore

[ghostlymoron]

I'd like to run my engine before putting boat in the water. I have no strainer and the seacock is very inaccessible so I can't easily disconnect the pipe to the water pump. The intake skin fitting is quite small (engine is VP MD1) and I've found a bit of small bore clear plastic pipe which is a snug fit inside it. Can I just dip this pipe in a bucket of water and start the engine? I'm concerned that it won't prime and hence wreck the impellor.
Plan 'B' is disconnect the feed pipe from the water pump, fit a short length of 1/2" hose which will go to a bucket. The bucket would still be below the water pump though.

 

[scottie]

Conventional method is hose into bucket inside boat at lowest level posible and bucket fed by water hose once started
Only run in with boat in cradle and with yards permission

 

[kolster]

I don't know what water pump you've got but on my engine its a 1/4" Jabsco and according to them it is,

"Self-Priming:
Pumps instantly, with dry
suction, lifts up to 3m (10ft); up to 8m (25ft)
when wetted."

So if you've got anything like that it should be be OK, the water line on the boat will probably be below the pump anyway.

 

[corbu]

The first time I tried this, with a fairly old impeller, I found that it worked better when I 'pre-filled' the tube leading to the bucket with water. (Disconnected the tube from the pump and poured water into it with a small funnel before reconnecting.)

This worked a treat, empties the bucket surprisingly quickly though so make sure that you can top it up with a hose!

 

[prv]

Plan 'B' is disconnect the feed pipe from the water pump, fit a short length of 1/2" hose which will go to a bucket. The bucket would still be below the water pump though.

That would be my choice - I think you'd be lucky to get the pump to prime with plan A.

Pete

 

[sailorman]

hang the bucket under the exhaust skin fitting with a plastic skin fitting + hose to the intake to recycle the water ( well most of it )

 

[Avocet]

If it has been out of the water for a while, and the pump impeller might be dry, fill the pipe with water and hold it higher than the impeller whilst turning the engine over a few times first.

 

[theoldsalt]

I have used a garden hose supplied from a mains tap. You only need a small trickle of water. When the water is flowing out of the end of the hose push it up the inlet skin fitting making sure it's a tight fit and won't fall out then start the engine.

 

[prv]

I have used a garden hose supplied from a mains tap. You only need a small trickle of water. When the water is flowing out of the end of the hose push it up the inlet skin fitting making sure it's a tight fit and won't fall out then start the engine.

The problem with that is if the flow is too great, and especially if the engine takes a while to get going, you risk filling the exhaust and then the cylinders. It's not a large risk (the stationary impeller should limit the flow, and it'll take a while to fill the exhaust) but it does exist. Personally I prefer to let the engine suck in the water at its own rate.

Pete

 

[theoldsalt]

The problem with that is if the flow is too great, and especially if the engine takes a while to get going, you risk filling the exhaust and then the cylinders. It's not a large risk (the stationary impeller should limit the flow, and it'll take a while to fill the exhaust) but it does exist. Personally I prefer to let the engine suck in the water at its own rate.

Pete

Thanks for making that point. That is certainly a possibility with an engine failing to start quickly. Luckily I have benefited from engines that fire up first time even after a winter layup.

 

[ripvan1]

Put some glycerine/grease on impellor before starting the operation, will help to lubricate a dry impellor

 

[SHUG]

I have used a garden hose supplied from a mains tap. You only need a small trickle of water. When the water is flowing out of the end of the hose push it up the inlet skin fitting making sure it's a tight fit and won't fall out then start the engine.

Absolutely NOT!!!!!
If you have a pressure supply to the engine you can back-fill the exhaust and flood the engine causing a hydraulic lock, bent con rods and a wrecked engine!!!!!

PS I see that others have pointed out this potential problem

 

[theoldsalt]

Absolutely NOT!!!!!
If you have a pressure supply to the engine you can back-fill the exhaust and flood the engine causing a hydraulic lock, bent con rods and a wrecked engine!!!!!

PS I see that others have pointed out this potential problem

I did say a trickle of water. Many engines are below the waterline but they do not suddenly flood with water as soon as the sea cock is opened. Yes it is a "potential" problem so care is needed. That is no reason to scare monger by saying "Absolutely NOT !!!!! " You might just as well state that we should never climb a mast because of the potential for falling.

 

[pcatterall]

We discussed a tank fitting into the base of SWIMBOs best bucket and fitting your hose to that. The bucket can be hung on the side of the boat.

 

[ghostlymoron]

All these are useful points but do not really solve my problem.
I don't see how you can prime a pipe with an open end surely it will just run out.
Any solution involving adjusting the pipework to the pump is EXTREMELY difficult because the pump is located at the back of the engine and accessed by crawling through the heads compartment.
If i could be sure the pump would prime quickly I'm tempted to grease the impellor and go with plan 'A'.

 

[ghostlymoron]

Yes I remember that conversation but was after a simpler way if possible.

We discussed a tank fitting into the base of SWIMBOs best bucket and fitting your hose to that. The bucket can be hung on the side of the boat.

 

[lw395]

I'd like to run my engine before putting boat in the water. I have no strainer and the seacock is very inaccessible so I can't easily disconnect the pipe to the water pump. The intake skin fitting is quite small (engine is VP MD1) and I've found a bit of small bore clear plastic pipe which is a snug fit inside it. Can I just dip this pipe in a bucket of water and start the engine? I'm concerned that it won't prime and hence wreck the impellor.
Plan 'B' is disconnect the feed pipe from the water pump, fit a short length of 1/2" hose which will go to a bucket. The bucket would still be below the water pump though.

Is this just some vague desire to run the motor or have you some doubt about it running?
It sounds like your boat does not make running the motor ashore easy. So unless there is a big benefit, don't bother.
Running it off load is of limited value anyway.
Can you remove the exhaust and hose water up the skin fitting to prime the impeller pump?
So long as you don't fill the exhaust no damage will be done.
I'd still not trust an impeller to lift water more than a foot or two.

Personally I'd want a strainer of some sort.
But it's nearly august, time it was wet.

 

[reeac]

All these are useful points but do not really solve my problem.
I don't see how you can prime a pipe with an open end surely it will just run out.
Any solution involving adjusting the pipework to the pump is EXTREMELY difficult because the pump is located at the back of the engine and accessed by crawling through the heads compartment.
If i could be sure the pump would prime quickly I'm tempted to grease the impellor and go with plan 'A'.

I always use whatI thought was the standard method of a bucket hung over the pushpin and under the exhaust with a hose running from a fitting in its base running to the cooling water inlet. Fill with water and off you go. The bucket will be above the cooling water inlet and so will promptly supply water to the pump, you don,t need a mains water supply nearby and the recirculating water will warm up and maybe dissolve some crud in the system. I push a short length of plastic water pipe into the exhaust to minimise loss of water by splashing.g

 

[prv]

Is this just some vague desire to run the motor or have you some doubt about it running?
It sounds like your boat does not make running the motor ashore easy. So unless there is a big benefit, don't bother.

In our yard, running the engine before lift-in after a winter ashore is encouraged. The lift can only be used at high water slack, so there's quite short window to get several boats shifted. Plopping into the water and then being unable to motor clear will not make you popular with the people behind!

Pete

 

[ghostlymoron]

How do you connect to the water inlet?

I always use whatI thought was the standard method of a bucket hung over the pushpin and under the exhaust with a hose running from a fitting in its base running to the cooling water inlet. Fill with water and off you go. The bucket will be above the cooling water inlet and so will promptly supply water to the pump, you don,t need a mains water supply nearby and the recirculating water will warm up and maybe dissolve some crud in the system. I push a short length of plastic water pipe into the exhaust to minimise loss of water by splashing.g