Help With Service Manual And Or Poppet Valve Replacement Because Of Engine Overheatin

[JohnMetta]

Good Afternoon,
First off the serial number of my 1998 Mercury 115hp 2stroke Outboard is OG722825 and if anyone has the detailed service manual that would be greatly appreciated. My engine is overheating only at idle speed. Once I move the throttle to 1500 RPMs, the temp stays at a steady 170 degrees. Whats the normal operating temp for this engine? The more throttle the less temperature. The stream of water is excellent. At higher temperatures the water is hotter, so I assume the thermostat is working correctly. I suspect it can either be water pump or the poppet valve. The boat is currently in the water so I'd like to try the poppet valve first. If anyone has any tips or how-to's on this, I'd really appreciate it.
Thanks,

John

 

[carholme]

Re: Help With Service Manual And Or Poppet Valve Replacement Because Of Engine Overhe

Your s/n comes up as:

MERCURY - (115 H.P. (1998 ))
Serial No: 0G722825 Model No: 1115412UD

Parts List for model 1115412UD:

100/115/125 H.P. 80 JET (4 CYLINDER) - Mercury, Mercruiser, Force, etc. Parts Lookup

Service manual is p/n: 90-830234

If you PM with an email address, I will send you a copy.

Water Pressure

@ 750 RPM (Idle) 2.0-4.0 psi (14-28 kPa)
@ 6000 RPM (WOT) 10.0-15.0 psi (69-103 kPa)

Gerry

 

[Faztbullet]

Re: Help With Service Manual And Or Poppet Valve Replacement Because Of Engine Overhe

Poppet valve only opens above 2500+rpm so unless it has debris under it holding it slightly open.If impeller hasn't not been changed in last 2 years its the culprit....

 

[JohnMetta]

Re: Help With Service Manual And Or Poppet Valve Replacement Because Of Engine Overhe

Thank a lot. I will change on Sunday. The local boat shop sold me this QUICKSILVER WATER PUMP UPPER REPAIR KIT part 46-96148Q8. Can I use this? They said Mercury Water Pumps are very generic and that this was the right one.

 

[Faztbullet]

Re: Help With Service Manual And Or Poppet Valve Replacement Because Of Engine Overhe

Wrong kit....correct one is 46-43024A7

 

[JohnMetta]

Re: Help With Service Manual And Or Poppet Valve Replacement Because Of Engine Overhe

Thank You Very Much