Yamaha 4-stroke 225 overheating

[ToddS]

Brand new to this forum....great find. Hopefully ya'll can help me out(?)<br /><br />I've got a 2002 Yamaha 4-stroke F225-TXRA with 30 hours on it from the orig owner from which I purchased a month ago. Upon startup I observe steady stream of discharge water both from behind the outboard (below the waterline) and from the pee valve. Discharge rate increases as RPM's increase as expected. I just bought the boat/motor and trailor and yesterday was first time in the water. Anyway after 5-10 minutes I got the overheating alarm. I never got the boat out of the no wake zone so all occured at idle RPM's. Needless to say I returned promptly to the dock 2 minutes or so later. This morning I ran a waterhose thru the garden hose attachment off the engine. Water appeared to circulate normally and discharge out the pee valve although not too strong, so I cranked the engine. Again the discharge appeared to be at a normal rate. I noted the time and after 5 minutes of watching the discharge and feeling the engine block all appeared to be okay, so I engaged the prop and ran idle for a couple minutes. Engine got a little warm to touch but not out of the ordinary. I disengaged and brought RPM's up to 1000. after just another minute or two (at the 10 minute mark) I got the overheat alarm. Engine block was quite warm to the touch. I immediately shut the engine down. <br /><br />What are your thoughts? I'm guessing something to do with the waterpump or thermostat but I'm not a mechanic and only speculating. Any suggestions? If it is a thermostat (not sure if there's 1 or 2) could this repair be done with keeping the boat in the water? Assuming it can and only issue would chance of losing a tool or so <br /><br />Appreciate the help and sorry for the loooong post.....just trying to get all the info out there.<br /><br />Thanks!

 

[rodbolt]

Re: Yamaha 4-stroke 225 overheating

if it has been run at all out of the water with no water to the pump odds are the pump is damaged. out of the water with the engine flush attachment can damage it as well. DO NOT run the motor on the hose attachment on the engine without the gearcase in the water.<br /> my bet is a cooling system maint is in order. the schedule for t-stats is 200 hours OR 1 year, the water pump is 200 hours OR 1 year and the pressure control valve is 200 hoiurs OR one year. its hours OR calender whichever occurs first. the t-stats take about an hour to change. the pressure control valve about 45 min the water pump about an hour. can be done in a lift or shallow water but its difficult and if you drop a fastener odds are its just gone.<br /> we have had issues on running them on the flush muffs. I use a bungee cord to help hold the muffs in position.<br /> could also be some debris in the pressure control valve<br />but were it me I would replace all the cooling system maint items and then you know what you have

 

[ToddS]

Re: Yamaha 4-stroke 225 overheating

rodbolt: Thanks. I just picked up a waterpump rebuild kit. where is the pressure control valve sit? I'm going to haul out the boat today and do the impeller job and I guess I should pick up two thermostats?<br /><br />appreciate any additional help.<br /><br />Oh, I never ran the motor on just the hose attachment....that I know better to do.<br /><br />Thanks!!!

 

[rodbolt]

Re: Yamaha 4-stroke 225 overheating

looking at the aft of the engine just below the cowl you will see a panel about 9 inches by 4 inches. loosen the two side cowls or just remove them and the remove the two fasteners holding the panel. remove the panel. sitting on a shelf looking part there is a 10mm hex holding a locking device on about a 1 7/16ths hex. remove the 10mm hex headed bolt, taking care not to lose the spacer. remove that large plastic hex. that is the valvle assy. no maint can be done to it other than inspection and rinse or replace. the t-stats are a ball to get to. inspect the water pump housing very carefully for any signs of melting. any melt is grounds for replacement. someplace on this forum is a posting for a 115 that contains all the info on how to replace your pump. its not illustrated well in the manual and there are some funny steps.<br />but its basically the same for all V yams since 95.if you wish to do the t-stats Ill try to outline it from memory for ya if needed.

 

[bigbrownbuku]

Re: Yamaha 4-stroke 225 overheating

a tip to remove the assembly atop the impellor.<br />i get 2 "1/2 drive" sockets on opposite sides of the drive shaft and use that as a lever point on the chrome cup. otherwise its the chisel.

 

[rodbolt]

Re: Yamaha 4-stroke 225 overheating

benC<br /> an easier way is to reinstall the pump insert over the impeller and use the insert as a fulcrum. I use two large screwdrivers at 90* from the retainer split line. I push in on both and twist the blades against the nylon and the cup. if it moves but does not unlock use the aft prop stopper and while pulling up on the shaft tap the retainer back down and try again. most I can get, if not its cut it off time. the retainer kit is only about 7 dollars. that way my knuckles dont get busted when the sockets slip. rodbolt bleeds easy anymore