115 hp jet drive

A

almost retired again

Chief Petty Officer
Joined
Feb 9, 2002
Messages
438
I'm having troubles with an overheat problem on a 115 hp jet drive Yahama. the starboard side sets off the overheat alarm. I have pulled and tested both of the thermostats, they open at 120 F. have replaced the water pump, still over heats. Pulled the stbd. head and looked for some kind of blockage, found nothing. I'm about ready to pull my hair out (what little there is left) This is a 2001 engine. Just thought that I would post and see if anyone else had any thoughts on this. This only happens at idle speeds.
 
R

rodbolt

Supreme Mariner
Joined
Sep 1, 2003
Messages
20,066
Re: 115 hp jet drive

hello<br /> test the pressure relief valve or better just install a new grommet.<br /> this valve will hang open slightly and dump water from the exhaust cover back to the powerhead adapter and out.if it leaks at an idle water pressure will be lower and the top of the stbd head will not fill with water. its a common sign of a hung or leaky valve. good luck and keep posting
 
A

almost retired again

Chief Petty Officer
Joined
Feb 9, 2002
Messages
438
Re: 115 hp jet drive

Thanks Rodbolt<br />I've worked in the marine buiness for about 25 years, but have had very little to do with Yamahas. Is the pressure relief valve that you are talking about located on the exaust cover?<br />I'm finaly retired and don't have access rto the service manuals that I had before, and I'm just trying to help a friend.<br />Thanks again
 
B

bossee

Senior Chief Petty Officer
Joined
Jul 18, 2002
Messages
727
Re: 115 hp jet drive

Hi,<br /><br />You can at least see the Electronic parts catalog<br />with drawings on US Yamaha website.<br /> http://www.yamaha-motor.com/products/categories02.asp?lid=5&lc=otb <br />Upper meny Parts & Serice, Parts Catalog,<br />Select Catalog Outboards in the list then Go.<br />Select for example F115TLRZ (2001 Outboard) if that is what You are intrerested in.<br />You will get a list of parts etc and drawings for them.<br /><br />There is also an Catalog for Jetdrives if you need any parts drawing specifically for Jet drives that is not covered in the outboards main Catalog.<br /><br />/Bo
 
R

rodbolt

Supreme Mariner
Joined
Sep 1, 2003
Messages
20,066
Re: 115 hp jet drive

hello<br /> yes that is where the valve is. remove the two 6mm bolts and if the cover is stuck tap it sideways. if your lucky the gasket wont stick. and btw the cover has a spring that is stout. when the gasket lets go it moves. if this cures the problem all is well. most cooling problems at idle are bad pump/pressure valve grommet issues.<br /> good luck and keep posting
 
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