Should I be worried "water pump"

[manboat]

Hi Guys,

Went out the other night only to find my water pump wasn't pumping really strong and when ever I accelerated the engine would cut out. Now I am guessing there is some sort of fail safe that cuts it out due to getting warm. Went back to the ramp and gave the hose a nice strong blow and she started working nicely again. No further problems that night. I then flushed the motor later that night and noticed the stream coming out is not strong at all certainly not as strong as when it's in the water. I pulled the bottom end off and had a look at the impeller and there was no obvious problems or cracks. I gave it a good blow again from the top and air was moving freely. Put everything back together run the motor again and still just flowing out very gently even if I increase the revs. The water coming out is nice and cool and there's no obvious signs of trouble it's just not as strong as what I am used to from our old boat with a 2 stroke.

Engine is a 90 4 stroke honda
Am I just being paranoid now?

[lethal098]

how long has the current impeller been in there for? i would be concerned, if it fails while underway you would not know until she overheated. I would think best to replace it.

cheers Lee

[manboat]

how long has the current impeller been in there for? i would be concerned, if it fails while underway you would not know until she overheated. I would think best to replace it.

cheers Lee

It was replaced at the last service under 12 months ago

[TimiBoy]

"If in doubt, check it out."

I'd do exactly that. Do a simple risk assessment - if it's not as strong as it should be, there is something wrong. Do you want to find out what's wrong when you are on the water?

Have it checked.

Cheers,

Tim

[ozscott]

Any noticeable loss of strength means its time for a water pump kit.

Cheers

[FNQCairns]

Hi Guys,

Went out the other night only to find my water pump wasn't pumping really strong and when ever I accelerated the engine would cut out. Now I am guessing there is some sort of fail safe that cuts it out due to getting warm. Went back to the ramp and gave the hose a nice strong blow and she started working nicely again. No further problems that night. I then flushed the motor later that night and noticed the stream coming out is not strong at all certainly not as strong as when it's in the water. I pulled the bottom end off and had a look at the impeller and there was no obvious problems or cracks. I gave it a good blow again from the top and air was moving freely. Put everything back together run the motor again and still just flowing out very gently even if I increase the revs. The water coming out is nice and cool and there's no obvious signs of trouble it's just not as strong as what I am used to from our old boat with a 2 stroke.

Engine is a 90 4 stroke honda
Am I just being paranoid now?

yeah you could be, still better safe than sorry. if the engine heads do not get hot then it cannot be overheating so you can check with your hand the efficacy of the water pump.

[Spaniard_King]

Any noticeable loss of strength means its time for a water pump kit.

Cheers

So I guess if the thermostat is jammed partially open it wouldn't give any of those symptoms

Manboat, it could be

Impeller
Thermostat
Stuck manual flush point
faulty overheat sensor
a conbination of the above

either way I will sort it for you check your email

[ozscott]

So I guess if the thermostat is jammed partially open it wouldn't give any of those symptoms

Manboat, it could be

Impeller
Thermostat
Stuck manual flush point
faulty overheat sensor
a conbination of the above

either way I will sort it for you check your email

Fair call Gary - I usually get the thermostats and water pump done at the same time thus my comment....I just dont muck around with low pressure - its impeller seals and thermostats at the one hit. But why would a faulty overheat sensor cause the pressure loss he is experiencing? I had an overheat condition in my Yammy once after all of the above was replaced and it turned about to be a small blockage in the head, but there was no pressure loss...he has both pressure loss and overheat warning. Further his impeller is 12 months old, so shouldnt that be the first thing to change anyway?

[Spaniard_King]

Scott,

It's possible that the overheat sensor is triggering too early, Cornel's engine runs a 72 degree thermostat hence they tend to run quite warm but they normally take a fair bit to overheat them. I do think it will be the thermostat, havent seen too many trashed impellors these days they seem to take a fair bit of punishment.

Either way I will let you know the outcome Monday night

[ozscott]

Garry - what sort of life are you typically seeing out of a Honda impeller - is there much difference if the engine is not used much?

Cheers

[Spaniard_King]

Scott, It varies depending on the boats usage.

Bluewater boats .. generally 200hrs no problem but if the boat sits for extended periods and the boat lives in the sun then it needs to be changed annually. For the cost involved most of my customer would rather a new impellor than a tow back from 50klm out.

Had a customer that got 1000hrs out of one over a 6 month period tho and he wasn't going to get into trouble if it failed.. that was his call.