Gun Maintenace and Repair - Valve Replacement

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Valve Replacement

Printed From: Tippmann Paintball
Category: Paintball Equipment
Forum Name: Gun Maintenace and Repair
Forum Description: Important info for keeping your marker in top shape
URL: http://www.tippmannsports.com/forum/wwf77a/forum_posts.asp?TID=181979
Printed Date: 12 October 2026 at 2:59pm
Software Version: Web Wiz Forums 12.04 - http://www.webwizforums.com

Topic: Valve Replacement

Posted By: Gimpy_Butzke
Subject: Valve Replacement
Date Posted: 06 June 2009 at 3:04pm

I replaced the valve in my 98C yesterday, I had problems getting over 240 FPS with HPA, and I was surprised to find a dead bug in my power tube. I have absolutely no idea how it managed to get in there and it looked like it was in there for quite some time.

Has anyone else had something like this happen to them? Also I'd like to hear any other odd stories about their maintenance and repair.

Replies:

Posted By: Gimpy_Butzke
Date Posted: 07 June 2009 at 6:58pm

So I tested the valve and am very very dissapointed.

Before replacing my valve I could only get 240fps. Now, after replacing the valve I can't even get to 200 fps. I shot an entire hopper with 2.5k pressure in my tank. I unscrewed the FVA so much it was peeking out of my marker.

Posted By: Yomillio
Date Posted: 07 June 2009 at 7:32pm

Did you just switch to HPA? It could be that your tank is low pressure (450 psi out of the regulator) vs. high pressure (850 psi output). Tippmanns need HP.

Also, have you tried replacing the drive spring? Velocity can decrease as your gun cycles more and the spring wears.

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Posted By: Gimpy_Butzke
Date Posted: 08 June 2009 at 12:55pm

I have a high tension spring, and another 98C that can get up to 280fps with the same tank. I also used my friends HPA tank on the ailing 98C and it still can't get above 240 (before replacing the valve.)

Posted By: Enos Shenk
Date Posted: 09 June 2009 at 6:43am

Two branches here, is it mechanical, or is it an air issue. Do you have a standard air setup? Nothing crazy like 3 expansion chambers in a row or an inline regulator or anything? If the air is fine...Either your mainspring is old and weak like folks are saying, or theres friction being generated somewhere.

Personally, I would check:

Is the gun cleaned and lubricated? And no, the "drops of oil in the ASA" trick is not lubricated. Take it apart and do it right.

Is the sliding surface areas inside the reciever halves rough? Run your finger along the areas where the front and rear bolt and linkage arm slide. Is it rough? If so, get some fine-grade steel wool (#00 grade) and polish the areas up. Dont go overboard, just get it smooth.

Are the reciever half bolts overtightened? It usually doesnt matter, but Ive seen some guns that had roughed up internal areas (see above) that if you overtightened the half bolts, the thing would barely work.

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Posted By: Gimpy_Butzke
Date Posted: 09 June 2009 at 12:11pm

Aside from a high tension spring my marker was exactly the same as the day I bought it. It is an old school flatline with a m4 stock, there are no regs or expansion chambers. The marker is also very well lubricated and clean.

I called Tippmann and they are sending me quite a few new parts. If something is still wrong after this I am sending it in rather than trying to fix it myself.

I'm hoping to get all the parts and get it fixed before Saturday so I can finally use it with HPA and all my new gear.

Posted By: Mack
Date Posted: 11 June 2009 at 11:33am

Gimpy_Butzke wrote:

I unscrewed the FVA so much it was peeking out of my marker.

This will not help. Normally the FVA only increases velocity during about the first four turns out from all the way in.

Try installing the air tank, then turning it back out about a quarter turn. If you get better results it means the pin in the ASA that opens the tank valve is blocking air flow.

Also try a CO2 and another air tank on your marker. In warm weather CO2 delivers at significantly more pressure than most compressed air tanks so if the marker only works better on CO2 you will know that for some reason your marker requires more pressure to operate. If it works better on both the CO2 and the other air tank, then you will know you have an air tank problem.

You mentioned that you are using a Flatline Barrel. Velocity problems will result if the Flatline barrel is not fully seated in the marker as air loss can occur around the end of the barrel. You should check this as well.

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