PRO XS 175 ISSUE?

[ride.race.live]

This picture is from a 2 stroke ATV I was tuning, ignore the black soot covered ring (still too rich) but the coloring on the ground strap and electrode isn't half bad on a fairly used plug. typically you want your plugs to come out close to this if not lighter... (keep in mind the ring shouldnt be soot black)

[potomacbassin]

fuel psi 112 +- 2/air 93 +- 2 around 15 lbs diff on pxs models with gray DI INJECTORS/ 10 psi diff non pxs

So last night I read in my service manual that the fuel pressure should be 89+/-2 and air should be 79+/-2. Are you sure it should be 112 for the 2.5 liters? Just want to make sure.

[JOE54]

did you look at pro xs gray direct injectors

[potomacbassin]

It doesn't mention anything about that.

[JOE54]

gray (pxs) direct injectors use higher psi than standard optis ,does your factory manual cover pxs mtrs ,look in front under fuel rail specs and air comp specs for 175 PXS

[potomacbassin]

Looks like my manual may be outdated.

[JOE54]

uh oh time for a new one /8m0057453

[SilverFox579]

I have the exact manual Joe mentioned and is dated May 2011. On page 1B-2 the 2.5L ProXS specs are listed as fuel side 109 +/- 2psi and air side 95 +/- 2psi. For others who might read this post, please note these specs are different than standard Optimax (why ProXS is in bold text).

[EuropeanAM]

I have the exact manual Joe mentioned and is dated May 2011. On page 1B-2 the 2.5L ProXS specs are listed as fuel side 109 +/- 2psi and air side 95 +/- 2psi. For others who might read this post, please note these specs are different than standard Optimax (why ProXS is in bold text).

+1... the GRAY Direct Injector engines will run 95/109 (or 94/108 as referred to in earlier days), plus or minus 2 psi

[potomacbassin]

UPDATE - So I picked my boat up today and did a test run on it. I must have two issues. They replaced the torn fuel diaphragm which fixed the rough cold start and it seems to idle better. They also replaced the air compressor reed plate under a service bulletin. However, my WOT "missing/slipping" still persists. It's almost like a hickup and it even started to do it on holeshot but normally at 5630 rpms. Per the tech's notes:

Compression test was 90 psi on all six cylinders and all had spark. Checked fuel pressure and it was within specification.

Any other ideas? I appreciate all your guys' help on this. I think we're almost there. I think the high end "slipping" started after I greased the 'belt tensioner'. Not sure if that's what it's called. Would this be a sign of a bad belt? I've never replaced it and it doesn't look worn but maybe it's stretched too much? Never experienced a bad belt so not sure what the symptoms are.

[JOE54]

idea of hrs on belt ???? new one would be easy to try for test

[potomacbassin]

200 Hours. About to complete my 4th year on it so I know Don's recommendation is 400/4 year replacement. I tried finding posts on how to replace this to no avail. I can't find which section in my service manual this is under. Do you have anything?

[JOE54]

just use 3/8 ratchet and short ext take tension off belt and remove shouldn't have to remove anything else, very simple, charging system and powerhead section shows tensioner

[Rickp]

Make sure the white numbers on the belt are not up side down.

[potomacbassin]

How do you adjust to the proper tension?

[EuropeanAM]

Let go of and remove the ratchet. Tension is controlled by a spring-loaded tensioner.

[SilverFox579]

Note belt routing, grooved side of belt to the inside, smooth side to outside, and follow replies #33 & #36, doesn't get any simpler than that.

[potomacbassin]

My manual just says under the alternator section to adjust the drive belt as outlined under "drive belt replacement and adjustment" However there is no section in my manual. Is it the red or yellow nut in the picture. If it's the yellow I'm seeing to torque down to 15 ft lbs. Can anyone confirm the torque specs and which nut?

[JOE54]

poto you don't have to loosen anything just take spring tension off of belt and replace,see square hole in pic that's where drive goes to remove tension, do not remove idler pulley or spring mount for this

[potomacbassin]

ah hah! Thanks man. All makes sense now. I'll keep you posted on the results. Again appreciate the help.