35 hp how do you back flush?

[landlock]

Hello Mates! I have a 35 hp 3555 ser 1542 new impeller installed,pump sey in place thermostat opens and still no water????
cranks and run everytime,but i shut her down at about 7sec. Could this be because of blockage? I watch the tube go into the powerhead. This is driving me nuts!1 I would like to back flush it to see if that helps but I can't seem to find it in my manual. Can anybody tell me the correct protcol?

I have it in a trash can and what seems to be plenty of water. I cannot use muffs because I have my water inlet right above the prop and it looks like a part of th water tube and goes into the bottom of the pump

 

[roscoe]

Re: 35 hp how do you back flush?

About the only thing you can do is take a hose and try to force water into the thermostat housing, remove the thermo first.

The try it, you may need to run the engine for longer than 7 seconds, try 40-50 seconds.

Mine takes a good 20+ seconds every time.

 

[pnwboat]

Re: 35 hp how do you back flush?

You may not have a problem at all. 7 seconds is not very long. Make sure the lower unit is submerged deep enough into the container. Water should be at least level with the cavitation plate if not higher. Usually takes 20 to 30 seconds of running before the water gets to the top of the block.

 

[wickware]

Re: 35 hp how do you back flush?

Are you sitting as deep as you can in the trash can? I have had 2-3? of water too low to cause my motor not to pump water. The water is almost too low in the attachment. My note ?on the drum? is to fill above the mid-leg extension. Which is 2-3" above the water-line in this attachment. It probably started pumping at that level and continued at this level.

This is 1970, 35 HP Chrysler vs the 55 showing. JOW

 

[soflaguy]

Re: 35 hp how do you back flush?

Have you run it without the thermostat? I had mulch or something acumulate at the therm. Without it, the mulch passed on through and cleared the blockage.

 

[soflaguy]

Re: 35 hp how do you back flush?

I also ran a little firehose nozzle on my hose down the thermostat housing. I sprayed some WD40 in there to make anything in there slippery to help it pass on through.

 

[landlock]

Re: 35 hp how do you back flush?

About the only thing you can do is take a hose and try to force water into the thermostat housing, remove the thermo first.

The try it, you may need to run the engine for longer than 7 seconds, try 40-50 seconds.

Mine takes a good 20+ seconds every time.

Thanks roscoe. I just didn't want to do any damage to the power head.
I will give it a whirl.

 

[landlock]

Re: 35 hp how do you back flush?

I also ran a little firehose nozzle on my hose down the thermostat housing. I sprayed some WD40 in there to make anything in there slippery to help it pass on through.

Thanks soflyguy,I'll try anything at this point!

 

[landlock]

Re: 35 hp how do you back flush?

Are you sitting as deep as you can in the trash can? I have had 2-3? of water too low to cause my motor not to pump water. The water is almost too low in the attachment. My note ?on the drum? is to fill above the mid-leg extension. Which is 2-3" above the water-line in this attachment. It probably started pumping at that level and continued at this level.

This is 1970, 35 HP Chrysler vs the 55 showing. JOW

Thanks for the pics wickware, we seem to be sitting about the same.
Am going to try and let it run longer and see what happens. Here we go!

 

[The Hammer]

Re: 35 hp how do you back flush?

I agree with the rest of the post here, I service mine in a garage can and it takes closer to a minute to pump water through the engine, I'll rev mine up a little till its pumping good.

 

[landlock]

Re: 35 hp how do you back flush?

Have you run it without the thermostat? I had mulch or something acumulate at the therm. Without it, the mulch passed on through and cleared the blockage.

Yes I tried that and it does the same. Thanks for the reply.:

 

[landlock]

Re: 35 hp how do you back flush?

I agree with the rest of the post here, I service mine in a garage can and it takes closer to a minute to pump water through the engine, I'll rev mine up a little till its pumping good.

Thanks for the reply. Will do!

 

[landlock]

Re: 35 hp how do you back flush?

You may not have a problem at all. 7 seconds is not very long. Make sure the lower unit is submerged deep enough into the container. Water should be at least level with the cavitation plate if not higher. Usually takes 20 to 30 seconds of running before the water gets to the top of the block.

Thanks for the reply pnwboat I will run it longer and I will post the results:

 

[emoney]

Re: 35 hp how do you back flush?

Make sure the impeller is seated in the driveshaft key. I just went through
quite a "overheating" issue. My 50 hp, initially had me believing it was a
"not enough water thing", but that wasn't the case. Once I got my lower
unit down and the impeller changed and water pump housing all cleaned and
freshened up, it now spits water pretty much as soon as it gets running,
or at least in the time it takes me to get back there and check it.
I haven't thought about how long it's running, but basically from the time
it takes me to start it, make sure it's idling ok after a little warm up, and then
climbing out of the boat to go and check, so I'm sure that's longer than
7 seconds. Then, the water spits out of the exhaust as it's supposed to.
And, ftr, I have the water just over the cavitation plate because my
trailer causes the boat to sit up rather high.

Also, make sure you got the water pump seated on the water tube when
you put it back together, too. If, for some reason, that's not together,
the water won't pump up to the head, which could be another cause of
not getting the water. This is something that could've happend because
the lower unit will go back without have that hose/line connected, and
it's something you couldn't see with the engine submerged in a can.
When you had the lower unit down, did you make
sure the impeller was turning? I checked mine by grabbing the driveshaft
and just turning it to verify the impeller was turning with it. To get the
'blades' bent in the right direction, turn the driveshaft counter clockwise.
Good luck and keep us informed.