over heat question

Finley

Seaman Apprentice
Joined
Jan 23, 2005
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30
yama 225TLRR 94 model.
Over heat alarm at trolling speed but not at speed. Will troll at approx 800 rpm for 30 min and get an alarm. Turn off and waited a few minutes and would start back up with no alarm and run at speed approx 3000 rpm OK. Back at 800 rpm and would get alarm after about 30 minutes.
Replaced T-stats and water pump (kit) last year.
Please offer suggestions on where to start.
Thanks
 

rodbolt

Supreme Mariner
Joined
Sep 1, 2003
Messages
20,066
Re: over heat question

I would start by removing the presure control valve grommet, carefully cleaning the corrosion from the pocket and replacing the grommet.
thats the normal indication of a presure control valve issue on a 2 stroke V yamaha.
could still be a damaged water pump, if it was ever started dry.
 

Finley

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Jan 23, 2005
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Re: over heat question (Rodbolt)

Re: over heat question (Rodbolt)

I did start it dry. Before leaving but only to see if it would start. Where is the pressure control valve grommet located and could this cause a surging or leaning out situation. It sounded like it would be missing a cylinder on the way back in running around 2600 rpm and then kick back in and out every so often
 

Ray Neudecker

Lieutenant Commander
Joined
May 25, 2004
Messages
1,656
Re: over heat question

Normally, the low speed heat problem is caused by the poppet valve sticking or a warped water pump housing. The surging is normally a fuel restriction..It sounds like you need to buy a factory service manual and get to work on basic maintence or get to a good servicer.
 

Finley

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Jan 23, 2005
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30
Re: over heat question

Just a few more questions please.
Is the poppet valve the same as the pressure control valve?
Also on the tach alarm indicators there is a what appears to be a low oil symbol and a high oil one. The arrow above the full one stays on. Right???
I checked the impeller last night. It was soft, flexible with no apparent damage. Keyway in place. But when I looked at the inside of the plastic housing, it looked very glazed as if the impeller cup had spun on it. The cup was seated in the hsg correctly when I removed it.
Any help from you guys is an honor.
Thanks for your time and sharing knowledge.
 

rodbolt

Supreme Mariner
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Sep 1, 2003
Messages
20,066
Re: over heat question

if the impeller housing shows any signs of melt its toast. yes the poppet and presure control valve is the same thing. key is to carefully clean the grommet pocket and replace the grommet, its under the t-stat housing looking thing on the lower stbd side of the exhast cover.

there were several styles of tachs, the one with the arrows shows oil level only. and only oil level in the remote tank is ok, when the remote level gets low the center arrow illuminates and no automatic oil transfer can occur. when the engine tnk level is low and the remote level is ok all the arrows may flsh or just the farthest to the left may flash indicating a low tank level.
a clogged filter in the remote tank will create a condition at higher speeds were the engine can use oil faster than it can transfer creating an alarm at higher speeds that goes away at low speeds. a bad trim sender can create a no transfer condition as well.
I think in that year range the overheat visual was in the speedometer with the low battery visual but I cant remember.
low battery,overheat and low engine oil level will all use the same horn and all will set RPM reduction in that year range.
when you first power up the tach you should see 3 arrows for a second or so while the tach self tests.
if you get a tone and no flashing arrows on the tach odds are its either overheat or low battery.
a bad connection anywhere from either battery post to the ECU can trigger a low battery alarm.
you cant miss a melted housing as it will look rather bubbly and discolored some. first place they melt is at the cup edges and where the shaft passes through the housing.
make sure you turn the drive shaft clockwise when reinstalling the impeller housing/cup assy, there is not enough room for the blades to properly orient themselves if installed backwards. I just use grease in the oring groove to retain the oring on that model.
no need for any speacial sealers. the other cause of low presure can be the rubber dam just aft and below the wear plate. remove it and the holder and clean any corrosion from them.
sometimes the corrosion will lift the dam slightly and create an air leak that is most noticible at low speeds and will cause low pressure at idle.
 

Finley

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Jan 23, 2005
Messages
30
Re: over heat question

Did not see any signs of melting in the hsg. I found the print out / location of the pressure valve so I'll clean and check it out.
Funny thing about that motor. Yamaha parts list is screwed up. Mine is a 94 model but they have the parts list backwards. 94 parts are listed under the 93 model. We found this out when ordering the oil sending unit last year.
Thanks for all your help. It sure is satisfying being able to fix things myself (with a little help). Thanks again.
 

rodbolt

Supreme Mariner
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Sep 1, 2003
Messages
20,066
Re: over heat question

it will be listed under 225tlrr
look on the yamaha parts website or use the parts smart at a yamaha dealer.
at the dealer parts smart has a where used on any model to cross check a part number and check for supercessions.
make sure you replace the grommet with a new one and dont drop it inside the housing, if you do, post it and ill explain how to retrieve it.
 

Finley

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Jan 23, 2005
Messages
30
Re: over heat question

What is the origintation of the rubber dam or seal damper into the metal base? I just want to make sure I put it in right. I can not tell on my drawing.

What position is the length long 20 degree bevel that is concave cut in relation to the w pump hsg? I just can't tell. I see that the metal base has rounded corners that faces the pump but I can not figure out the rubber seal damper.
Thanks again.
 
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