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GT500 carbs: Starter plunger is stuck

Posted: Thu Sep 06, 2018 7:41 am
by GT500-2stroke
1975 GT500:

One of the starter plunger ( is it also called choke ? ) is stuck inside the body.
The other one is moving inside and out freely.

I am trying to decide what are my options at this point?

1. Just try to get it working. But How?
2. Leave it alone, since the other one is working.
Will this approach work?
What are the compromises with this approach?
3. Just get a T500 carbs from eBay.
:
:

Appreciate any help..

Re: GT500 carbs: Starter plunger is stuck

Posted: Thu Sep 06, 2018 11:00 am
by GTandcbr
You must persevere and free the stuck plunger. Try soaking it with carb cleaner or WD40. It will come free eventually.

Re: GT500 carbs: Starter plunger is stuck

Posted: Thu Sep 06, 2018 11:38 am
by GT500-2stroke
GTandcbr wrote:You must persevere and free the stuck plunger. Try soaking it with carb cleaner or WD40. It will come free eventually.
Ok.
Also can you suggest a strong acid that can be used selectively only on plunger?
Which store might sell a strong acid?
What would be the name of acid?

Meanwhile I will continue to work with carb cleaner, vinegar, WD40..

Re: GT500 carbs: Starter plunger is stuck

Posted: Thu Sep 06, 2018 12:25 pm
by GTandcbr
Don't use anything corrosive unless you intend to replace the plunger as the bottom of the plunger has a rubber seal that will render it useless.

Re: GT500 carbs: Starter plunger is stuck

Posted: Thu Sep 06, 2018 12:57 pm
by dorT500
GT500-2stroke wrote:
GTandcbr wrote:You must persevere and free the stuck plunger. Try soaking it with carb cleaner or WD40. It will come free eventually.
Ok.
Also can you suggest a strong acid that can be used selectively only on plunger?
Which store might sell a strong acid?
What would be the name of acid?

Meanwhile I will continue to work with carb cleaner, vinegar, WD40..


There is a thin rubber membrane in the bottom of the enrichment circuit's (how's that Rizingson? :wink: ) plunger. It may already be past saving but try a slow, gentle approach.
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I would not use ANY aggressive solvent on it. Actually, I would not even use vinegar. WD40 evaporates if you are just spraying so only soaking in a bath of the stuff will help.......maybe.

Purchase this at any auto parts supply or maybe Wal-Mart. There is a similar procduct with the brand name of Kroil or Kano AeroKroil. Spray it in there and let it sit all day and then spray it again and let it sit overnight....go all day again if you have to. Just remember, you may not be pulling on just the plunger but also that rubber membrane. Good Luck



Image

Re: GT500 carbs: Starter plunger is stuck

Posted: Thu Sep 06, 2018 1:02 pm
by dorT500
GTandcbr wrote:Don't use anything corrosive unless you intend to replace the plunger as the bottom of the plunger has a rubber seal that will render it useless.
ooops :oops: I was still typing away and uploading pics while you posted the second time. Sorry... I did not realize. :) You gave the good warning also.

Re: GT500 carbs: Starter plunger is stuck

Posted: Thu Sep 06, 2018 1:21 pm
by dorT500
uh oh :| .....forget about what I said about using PB Blaster. I started thinking about it and realized I should have checked out if it was safe for rubber. From a quick search it looks like it IS NOT. Sorry about that, but in case you have never used them, it and Kroil penetrating oils are fantastic products for their intended use.

Re: GT500 carbs: Starter plunger is stuck

Posted: Thu Sep 06, 2018 6:53 pm
by tz375
WD40 or PB are fine. You will replace the plunger anyway because the seal at the bottom is probably hard and worn by now.

The plunger can usually be carefully levered out or use a pair of needle nose pliers to turn it as you slowly pull the plunger out

Re: GT500 carbs: Starter plunger is stuck

Posted: Tue Sep 11, 2018 9:02 pm
by GT500-2stroke
GTandcbr wrote:You must persevere and free the stuck plunger. Try soaking it with carb cleaner or WD40. It will come free eventually.
Sorry, do you mean to say soak the 'entire' carb or just 'spray' on the starter assembly?

Re: GT500 carbs: Starter plunger is stuck

Posted: Tue Sep 11, 2018 9:03 pm
by GT500-2stroke
GTandcbr wrote:Don't use anything corrosive unless you intend to replace the plunger as the bottom of the plunger has a rubber seal that will render it useless.
Ok. got it.

Re: GT500 carbs: Starter plunger is stuck

Posted: Tue Sep 11, 2018 10:11 pm
by GT500-2stroke
tz375 wrote:WD40 or PB are fine. You will replace the plunger anyway because the seal at the bottom is probably hard and worn by now.

The plunger can usually be carefully levered out or use a pair of needle nose pliers to turn it as you slowly pull the plunger out
So far no success using WG40 and Carb cleaner, along with gentle tapping.

Think of using heat and cold.

What do you think about heat and cold?
Any other ideas?

Re: GT500 carbs: Starter plunger is stuck

Posted: Tue Sep 11, 2018 11:29 pm
by Alan H
Soak it all in diesel for a day or two. Great stuff for softening 'stuff' without hurting alloys.

Re: GT500 carbs: Starter plunger is stuck

Posted: Wed Sep 12, 2018 1:44 am
by GT500-2stroke
Alan H wrote:Soak it all in diesel for a day or two. Great stuff for softening 'stuff' without hurting alloys.
Will try diesel.

Do you think applying heat is a bad idea?
( if diesel does not work i.e. )

Re: GT500 carbs: Starter plunger is stuck

Posted: Wed Sep 12, 2018 8:01 am
by Alan H
Let the diesel soak for a couple of days first.

Re: GT500 carbs: Starter plunger is stuck

Posted: Wed Sep 12, 2018 8:40 am
by Evans Ward
I'd hold off on the heat as you can easily damage/ melt the carb body. You have to be patient and give the penetrant some time to work on it's on.