Opti-max won’t idle

[Godluvn]

Hello all!
I’m new to this board, but have loved the helpful posts for years!

I, unfortunately, can’t seem to find this senecio, so I’ll throw it out there...

I’m trying to help a buddy who has an 08 Optimax 115. It will idle for about 10 seconds then start surging, and eventually die. It starts right back up, but then repeats the surging and dies!

We've changed the plugs, checked air pump filter, replaced the main screw in fuel filter.

The fuel bulb was replaced last year.

It appears to run lean right before dying(it’ll rev up about 500+ rpm)

I checked fuel pressure at the rail, and it goes up as the rpm’s rise(right before it dies), so I don’t believe it’s a delivery problem, but obviously don’t know...

Any help is super appreciated!

Thx, Chris~

 

[racerone]

Do a compression test..---Check operation of air compressor.

 

[Faztbullet]

Bad tracker valve....

 

[Godluvn]

Can I test the tracker valve, or just R&R....?

 

[schematic]

What is the serial number. Some 115 don't have tracker valves. What are the pressures at the rail and at the vapour separator? What plug number did you put in?

 

[Godluvn]

This one has a Tracker valve. I removed it today, did a visual as well as “Gatorade bottle check”. It appears to be fine, but not sure...
the spark plugs are the factory listed NGK Ir’s

I’m getting roughly 33psi@vapour seperator, and 80/90 on the rail (this was with engine running at approx 1800 rpm)

When I pulled the new plugs today, to do a compression check, they were soot black, indicating a “Pig Fat” condition!

compression check came back at 115-119psi.

Do I throw a diaphram in the Tracker just to see...? It was $130, that I’d like to not spend if not necessary...

 

[Godluvn]

At idle, the pressures, on the rail, bounce about 20psi each, and run about 20psi lower than at 1800 rpm. Is that normal...?

 

[schematic]

take the compressor belt off. Apply 90psi shop air to the air test port. See if idle improves. Also list motor serial number and fuel /air pressure at idle

 

[tlh 178]

check your fuel lines. the inner fuel lines will collapse and restrict your fuel . won't cost you anything to check. regular gas with ethanol will damage the inner liner. also you can find tracker valve on fleabay for 90.00 or so.

 

[schematic]

if you want to check the tracker valve, put a pressure gauge on the fuel port. Apply shop air to the air port and look for an increase in pressure on the fuel side.....If the fuel side increasing in pressure in a minute or so, the diaphragm is leaking