XR2 Fuel Pump Kits

[chadbenton]

If I were to rebuild my fuel pump, do I just need a gasket set or are there any other hard parts that I might need. I have the older style pump, not the square one. The only kit I can find is one from Sierra and it is just gaskets. Mercury only sells these in a complete engine gasket set. On to another subject. How does the poppet valve work. Is it a bi-metal spring that should be replace. Could not find any problems with any of it. Thermostats, mine had two types in it. One that opened in and the other opened outward. Could this cause any problems.

 

[Laddies]

Re: XR2 Fuel Pump Kits

The only differance between the Sierra kit and one from Mercury is the merc kit comes with check valves and the sierra don't
The popit valve is a pressure activated relief valve, that at higher RPM is opened by water pressure in the engine that lets water excape the powerhead through anouther water passage to improve high speed cooling

 

[gss036]

Re: XR2 Fuel Pump Kits

I would think someone installed one of the thermostats backwards. They both should work the same, letting hot water out of the block.

 

[rodbolt]

Re: XR2 Fuel Pump Kits

the seirra and OMC t-stats are self flushing and the poppit extends away from the hot water, the OEM stats the poppit retracts towards the hot water and are more prone to clogging.
really wont matter which you have as long as the are operating as desighned.
merc sells a diaphram kit for both V style fuel pumps.

 

[chadbenton]

Re: XR2 Fuel Pump Kits

My plans are to replace both thermostats with the Sierra's, Replace the diaphragm and seals on the poppet valve. Remove the lower unit, replace impeller, inspect all components and verify water flow through lower unit, block and heads. Also rebuild fuel pump and carbs and verify proper jetting of carbs. I plan on installing a water pressure guage, new sending unit and temp guage. You guys said to install water pressure port between heads. Could you tell me exactly where to install the fitting and what kind of pressure shoud I expect. Also, how much pressure drop is there when the poppet valve opens, so that I can know for sure it is working.....