F225 Overheat alarm problem

[pparke]

I have a problem with the overheat alarm. It only happens at low rpm in a trailing sea. The pisser tube is not flowing hard like it should so I replaced the water pump impeller but it made no difference and the impeller looked fine. I am Thinking that the theromostat might need replacing. What else would make the flow not hard. I am planning on doing this myself but need some advice. First , where can I get a service manual for a F225 because I would not know where to start looking for a thermostat? Second, any other ideas? Thanks

 

[gw204]

Could be t-stat. Could be poppit valve (if the 4-stroke has one). Could also be severe exhaust corrosion. Look here:

http://www.thehulltruth.com/boating-for ... check.html

http://www.thehulltruth.com/boating-for ... epair.html

http://www.thehulltruth.com/boating-for ... rdown.html

 

[Brent]

I have 02 F225. How many hours on the motor? Was a complete water pump replacement performed or a partial (impeller, partial rebuild)? Maybe the cup has wear or other issues might exist. I would replace the thermostat when the water pump is serviced.
I have a new poppit valve but have not installed it. SIM Yamaha web site has several online tutorials with images for the F225. see www.simyamaha.com
I have Clymer (~$32) and Yamaha (~$90) shop manuals. Both are fine but I also print SIM's articles and parts diagrams and keep in a 3 ring binder. Andy at SIM is super person to ask for advice and his prices are low and provides inexpensive fast shipping.
On the flip side, mechanical parts are fine and there is build up and need Salt-away treatments.

 

[CaptainJim]

i had similar issues at idle on my 200 HPDI in idle in the water.. at higher RPMs no problems, but idle was doom..I changed the Tstats (which were BAD shame on me) and did the water pump (motor only had one season on water pump) and the water pump plate had a slight groove in it, barely noticeable unless you ran a fingernail across it. I had asked the mechanic to do a whole kit, but i cannot be sure he didn't just pay me lip service and put an impeller in.

spend the extra $20 and get the whole kit - in my case the impeller was pristine, it was the steel backing plate which was worn.

start with tstats, poppet. water pump. Its about $100 in parts that will save your $18k engine.

 

[Striperswiper]

I'm tearing one down right now for a friend.
Google
exhaust tube corrision yamaha.

The exhaust tube on these motors corrodes and causes the motor to overheat at idle and low rpms.

The parts are aound 2000 and the labor the same at the dealer.

Drop your lower unit and look in the exhaust.
If it looks pitted DO NOT RUN YOUR MOTOR.

You'll blow your motor up.

 

[Striperswiper]

see these photos

viewtopic.php?f=19&t=9822