Fuel/Air Pressure Gauge question HELP PLEASE

[balistikb]

I am trying to diagnose a problem on my 1999 225 Optimax. Currently the optimax will not start. I know there is spark because shooting some starter fluid helped the engine start ( i later found out not to do this).
So having the service manual I wanted to check out my fuel system since this is the next logical choice.
In the manual it says I need two special tools a Single fuel/air pressure gauge 91-16850A2 and a Dual Fuel/Air pressure gauge 91-852087A1.
It also says I could convert a 100psi gauge to a 160psi gauge by ordering a part.
So my question is,
1. if I am testing the fuel pressure test valve and the air pressure test valve, the manual says it should be 80 and 90. Why would I need a 160 psi tester if what I am testing should be 90 and 80 psi?
2. I cannot afford the tester that the manual says to get so I looked around and found this one
http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=92699
I fits but I get a reading of about 50psi so I am not sure if it is working correctly.
Could someone please help me out here with some direction???
Thank you

 

[JustJason]

Re: Fuel/Air Pressure Gauge question HELP PLEASE

you need a high psi gauge for safety. if there is a problem with the fuel pressure regulator, the fuel pump, or the air compressor regulator and the gauge can't handle it, the gauge can blow up in your face/hands.

Shooting starting fluid does not mean you have good spark. Weak spark will light starting fluid, starting fluid will also self ignite is the pressure is high enough. Also, starting fluid is bad in a 2 stroke anything because it strips the oil off the bearing.

You really need the mercury gauges because they are calibrated, and opti's are picky about the pressures. The thing about off the shelf gauges, wether they are compression, fuel pressure, air pressure etc is that no 2 gauges read the same unless you pay extra for factory calibrated gauges.

 

[balistikb]

Re: Fuel/Air Pressure Gauge question HELP PLEASE

I understand your point but unfortunately I cannot afford those gauges and I would like to work on my boat.

 

[Jeff_G]

Re: Fuel/Air Pressure Gauge question HELP PLEASE

Unfortunately with an Optimax if you want to work on it you will need the proper tools. This includes a DDT scan tool or the software for a laptop.
Can you properly diagnose or work on your car? Antilock brakes? Air pressure monitors?
Sorry just can't be done.

BTW you need liquid filled gauges to test the air and fuel pressures.

 

[balistikb]

Re: Fuel/Air Pressure Gauge question HELP PLEASE

Thank you, I guess I will start looking to see if I find a used one.