Hi all. Will from New Zealand here.
I am having problems sorting outmy old HF 105's overheating issue. So far i have replaced the water pump, impeller, thermostat and temperature sensor. All of the compressions (cold) are approx. 125. Since installing the new impeller plenty of water is coming out of the two vents as well as the pee hole I installed. The over temp alarm only goes off at high revs, and stops within 10 or so seconds after slowing down to non-planing speeds.
I replaced the water pump as the old one was falling apart after
ingesting quite a bit of mud/stones after becoming beached a few
months back.
Apart from this the old girl goes great. A knowledgeable mechanic told
me (with an evil grin on his face)that it would probably be the Water
Bypass Valve - my Clymer manual doesn't even mention the existence of
one.
When it happened the other day I did a bit of on the water fiddling
and removed the thermostat - the alarm didn't go off after this, but I
reckon that it's fitted for a reason, so it should be there.
Funny thing - when i was checking it out the motor seemed to run much
better (faster) with the cowl off - my wife complained about the noise
though!
In order to gain access to the bypass hole (105 '75) for cleaning, I got out the trusty hole saw and drilled a 4 cm diameter hole through the bottom
cowling. I can always cover it with a 'service' plate. I cleaned it
all out and then I reasoned that if I forced water down the head
cooling hole (after the thermostat), water should come out the water
bypass hole, right? Wrong! What actually gets cooled first - the
cylinders? The head? I tried to force water into the bypass hole to -
no go. Do I have a major blockage?
Even though the compressions checked out ok, I removed the head (that is a story in itself) and I noticed that one of the combustion chambers was very clean - that would suggest water ingress?
I've now got to order a new head gasket, but i don't want to put it all together unless the cooling system is working as it should. I can't find any obvious blockages, and now everything is pretty clean. It's a good old motor and I don't have the $$$ to replace it (currently unemployed, waiting for new job to start).
Why doesn't any water go to the bypass hole????
Thanking you all in advance!
I am having problems sorting outmy old HF 105's overheating issue. So far i have replaced the water pump, impeller, thermostat and temperature sensor. All of the compressions (cold) are approx. 125. Since installing the new impeller plenty of water is coming out of the two vents as well as the pee hole I installed. The over temp alarm only goes off at high revs, and stops within 10 or so seconds after slowing down to non-planing speeds.
I replaced the water pump as the old one was falling apart after
ingesting quite a bit of mud/stones after becoming beached a few
months back.
Apart from this the old girl goes great. A knowledgeable mechanic told
me (with an evil grin on his face)that it would probably be the Water
Bypass Valve - my Clymer manual doesn't even mention the existence of
one.
When it happened the other day I did a bit of on the water fiddling
and removed the thermostat - the alarm didn't go off after this, but I
reckon that it's fitted for a reason, so it should be there.
Funny thing - when i was checking it out the motor seemed to run much
better (faster) with the cowl off - my wife complained about the noise
though!
In order to gain access to the bypass hole (105 '75) for cleaning, I got out the trusty hole saw and drilled a 4 cm diameter hole through the bottom
cowling. I can always cover it with a 'service' plate. I cleaned it
all out and then I reasoned that if I forced water down the head
cooling hole (after the thermostat), water should come out the water
bypass hole, right? Wrong! What actually gets cooled first - the
cylinders? The head? I tried to force water into the bypass hole to -
no go. Do I have a major blockage?
Even though the compressions checked out ok, I removed the head (that is a story in itself) and I noticed that one of the combustion chambers was very clean - that would suggest water ingress?
I've now got to order a new head gasket, but i don't want to put it all together unless the cooling system is working as it should. I can't find any obvious blockages, and now everything is pretty clean. It's a good old motor and I don't have the $$$ to replace it (currently unemployed, waiting for new job to start).
Why doesn't any water go to the bypass hole????
Thanking you all in advance!