WT 813 Syssa Carb Won't Pop
#1
Thread Starter
My Feedback: (62)
Join Date: Dec 2001
Location: Vineland,
NJ
Posts: 3,856
Likes: 0
Received 0 Likes
on
0 Posts
WT 813 Syssa Carb Won't Pop
I was having some idle issues with an "almost" broken in Syssa.
I would have to leave the idle around 3000 rpm and after about 20 seconds or so like on final,
the rpm would just drop out, and sometimes the engine would just die.
I twiddled and tweaked the needles, tried different prop loads etc. to no avail.
The ignition seem to be a newer style RC Xcel, so it's not one of those #4's with no curve.
I decided to check the pop off pressure and was surprised.
My gauge goes to 30 psi and the carb still wouldn't pop.
I checked and adjusted the metering lever height, put a kit in it and tried again, same thing.
Got the old Walbro spring kit out and tried a couple of shorter and lighter springs but same thing, 3o psi and no pop.
Decided to run it just for kicks and it did seem better, but it still bugs me that I can't get it to pop.
Every carb I've ever adjusted would go off between 12 and 15 psi.
Can it be something with the accelerator pump feature of the Syssa carb?
I didn't see anything different in the carb that looked like a pump though.
Thanks for any ideas
Bob
I would have to leave the idle around 3000 rpm and after about 20 seconds or so like on final,
the rpm would just drop out, and sometimes the engine would just die.
I twiddled and tweaked the needles, tried different prop loads etc. to no avail.
The ignition seem to be a newer style RC Xcel, so it's not one of those #4's with no curve.
I decided to check the pop off pressure and was surprised.
My gauge goes to 30 psi and the carb still wouldn't pop.
I checked and adjusted the metering lever height, put a kit in it and tried again, same thing.
Got the old Walbro spring kit out and tried a couple of shorter and lighter springs but same thing, 3o psi and no pop.
Decided to run it just for kicks and it did seem better, but it still bugs me that I can't get it to pop.
Every carb I've ever adjusted would go off between 12 and 15 psi.
Can it be something with the accelerator pump feature of the Syssa carb?
I didn't see anything different in the carb that looked like a pump though.
Thanks for any ideas
Bob
#2
My Feedback: (2)
RE: WT 813 Syssa Carb Won't Pop
No experience with pop off pressures. Thank God I've never had to visit that. I look to see if the lever is level with that raised reidge, then move on.
What I wanted to share was I think that if you have taken the potential for the ignition to be causing that problem out of the picture, it's almost guaranteed that your low speed is too lean. If it's not the low speed needle causing it (which would have been my bet), there's also the possibility you could have a vacuum leak? Could be anywhere in the intake path, crankcase, or cylinder to crankcase joint? Sometimes you'll see a fuel stain at the leak, but not always.
Have you set the low to 1.5 and the high to 2 turns (WAY FAT), then start your carb adjustment procedure over again?
Maybe something to think about if you haven't already. Best of luck!
What I wanted to share was I think that if you have taken the potential for the ignition to be causing that problem out of the picture, it's almost guaranteed that your low speed is too lean. If it's not the low speed needle causing it (which would have been my bet), there's also the possibility you could have a vacuum leak? Could be anywhere in the intake path, crankcase, or cylinder to crankcase joint? Sometimes you'll see a fuel stain at the leak, but not always.
Have you set the low to 1.5 and the high to 2 turns (WAY FAT), then start your carb adjustment procedure over again?
Maybe something to think about if you haven't already. Best of luck!
#3
Thread Starter
My Feedback: (62)
Join Date: Dec 2001
Location: Vineland,
NJ
Posts: 3,856
Likes: 0
Received 0 Likes
on
0 Posts
RE: WT 813 Syssa Carb Won't Pop
Thanks for the thoughts.
I adjusted the low end from one end to the other with no change.
All of the gaskets seemed to be OK when I took the carb off.
I ordered some spare parts from Syssa but don't expect an acknowledgement to my order till Spring or better.
Their service is horrible.
Take care
Bob
I adjusted the low end from one end to the other with no change.
All of the gaskets seemed to be OK when I took the carb off.
I ordered some spare parts from Syssa but don't expect an acknowledgement to my order till Spring or better.
Their service is horrible.
Take care
Bob
#4
RE: WT 813 Syssa Carb Won't Pop
ORIGINAL: bob_nj
I was having some idle issues with an "almost" broken in Syssa.
I would have to leave the idle around 3000 rpm and after about 20 seconds or so like on final,
the rpm would just drop out, and sometimes the engine would just die.
I twiddled and tweaked the needles, tried different prop loads etc. to no avail.
The ignition seem to be a newer style RC Xcel, so it's not one of those #4's with no curve.
I decided to check the pop off pressure and was surprised.
My gauge goes to 30 psi and the carb still wouldn't pop.
I checked and adjusted the metering lever height, put a kit in it and tried again, same thing.
Got the old Walbro spring kit out and tried a couple of shorter and lighter springs but same thing, 3o psi and no pop.
Decided to run it just for kicks and it did seem better, but it still bugs me that I can't get it to pop.
Every carb I've ever adjusted would go off between 12 and 15 psi.
Can it be something with the accelerator pump feature of the Syssa carb?
I didn't see anything different in the carb that looked like a pump though.
Thanks for any ideas
Bob
I was having some idle issues with an "almost" broken in Syssa.
I would have to leave the idle around 3000 rpm and after about 20 seconds or so like on final,
the rpm would just drop out, and sometimes the engine would just die.
I twiddled and tweaked the needles, tried different prop loads etc. to no avail.
The ignition seem to be a newer style RC Xcel, so it's not one of those #4's with no curve.
I decided to check the pop off pressure and was surprised.
My gauge goes to 30 psi and the carb still wouldn't pop.
I checked and adjusted the metering lever height, put a kit in it and tried again, same thing.
Got the old Walbro spring kit out and tried a couple of shorter and lighter springs but same thing, 3o psi and no pop.
Decided to run it just for kicks and it did seem better, but it still bugs me that I can't get it to pop.
Every carb I've ever adjusted would go off between 12 and 15 psi.
Can it be something with the accelerator pump feature of the Syssa carb?
I didn't see anything different in the carb that looked like a pump though.
Thanks for any ideas
Bob
Capt,n
#5
My Feedback: (98)
Join Date: Feb 2002
Location: The Villages, Florida NJ
Posts: 4,677
Likes: 0
Received 0 Likes
on
0 Posts
RE: WT 813 Syssa Carb Won't Pop
ORIGINAL: bob_nj
I adjusted the low end from one end to the other with no change.
I adjusted the low end from one end to the other with no change.
#8
My Feedback: (19)
RE: WT 813 Syssa Carb Won't Pop
I really didn't care for the WT 813 carb on the Syssa I owned. Mine also developed a similar low speed problem that I could not resolve. This carb is a bit different from non-accelerator pump versions as there are several parts built into the main body of the carb to make the pump work. This includes a non user replaceable one way valve that on my carb seemed to deteriorate. I thought that maybe some pieces from this valve got into the various low speed fuel passages causing problems. I pretty much left it at that and simply changed the carb to the one used on the current Zenoah G-26 and never looked back. Sorry, I don't remember the WT model number for the carb as I am at work and don't have the info here. Another good carb choice might be the one from a DLE30. Even when it was working OK, I didn't like the WT813 mostly because of the accelerator pump. I know some people like this carb, I did not.
Even later, I replaced the Syssa with a DLE30 .... and never looked back. The DLE just fits my preferences better and in no way am I putting down the Syssa as it is a very high quality engine.
Even later, I replaced the Syssa with a DLE30 .... and never looked back. The DLE just fits my preferences better and in no way am I putting down the Syssa as it is a very high quality engine.
#9
Thread Starter
My Feedback: (62)
Join Date: Dec 2001
Location: Vineland,
NJ
Posts: 3,856
Likes: 0
Received 0 Likes
on
0 Posts
RE: WT 813 Syssa Carb Won't Pop
Thanks Truckracer
It's good to hear that someone else had a similar issue.
Thought I was losing my mind.
Suposedly a Walbro 645 works ok.
I'll wait to get one from Syssa and see how it shakes out.
Thanks
Bob
It's good to hear that someone else had a similar issue.
Thought I was losing my mind.
Suposedly a Walbro 645 works ok.
I'll wait to get one from Syssa and see how it shakes out.
Thanks
Bob
#10
My Feedback: (19)
RE: WT 813 Syssa Carb Won't Pop
ORIGINAL: bob_nj
Thanks Truckracer
It's good to hear that someone else had a similar issue.
Thought I was losing my mind.
Suposedly a Walbro 645 works ok.
I'll wait to get one from Syssa and see how it shakes out.
Thanks
Bob
Thanks Truckracer
It's good to hear that someone else had a similar issue.
Thought I was losing my mind.
Suposedly a Walbro 645 works ok.
I'll wait to get one from Syssa and see how it shakes out.
Thanks
Bob
I also just remembered that when my problem developed, the high speed needle adjustments were also less effective. Fyi, the carb screen was always perfectly clean so no outside crud got into the carb.
#11
Senior Member
My Feedback: (4)
Join Date: Jul 2002
Location: Somewhere,
DC
Posts: 9,825
Likes: 0
Received 0 Likes
on
0 Posts
RE: WT 813 Syssa Carb Won't Pop
The accelerator pump is a little plunger that fits into a hole under the carb shaft...The shaft is milled halfway across to push the plunger as the shaft rotates...It's not really necessary on a 2 stroke gasser engine, it's made for a chainsaw where the trigger is pushed faster than the throttle on the plane...
The 201 carb from a DA 50 would work, so would a WT76A or the 645 carb from a G26.....
The 201 carb from a DA 50 would work, so would a WT76A or the 645 carb from a G26.....
#13
My Feedback: (19)
RE: WT 813 Syssa Carb Won't Pop
ORIGINAL: bob_nj
Thank you sir!
So could the pump be the reason it doesn't pop like a non-pumed carb?
Thank you sir!
So could the pump be the reason it doesn't pop like a non-pumed carb?
#14
My Feedback: (19)
RE: WT 813 Syssa Carb Won't Pop
ORIGINAL: Antique
The accelerator pump is a little plunger that fits into a hole under the carb shaft...The shaft is milled halfway across to push the plunger as the shaft rotates...It's not really necessary on a 2 stroke gasser engine, it's made for a chainsaw where the trigger is pushed faster than the throttle on the plane...
The 201 carb from a DA 50 would work, so would a WT76A or the 645 carb from a G26.....
The accelerator pump is a little plunger that fits into a hole under the carb shaft...The shaft is milled halfway across to push the plunger as the shaft rotates...It's not really necessary on a 2 stroke gasser engine, it's made for a chainsaw where the trigger is pushed faster than the throttle on the plane...
The 201 carb from a DA 50 would work, so would a WT76A or the 645 carb from a G26.....
#15
Senior Member
My Feedback: (4)
Join Date: Jul 2002
Location: Somewhere,
DC
Posts: 9,825
Likes: 0
Received 0 Likes
on
0 Posts
RE: WT 813 Syssa Carb Won't Pop
The one I have here is a WT624..Under the extra welch plug is a very fine screen, no rubber pieces anywhere...the hole leads to the center of the venturi, before the other small holes that control the idle and mid range mixture...
#17
My Feedback: (19)
RE: WT 813 Syssa Carb Won't Pop
ORIGINAL: Antique
The one I have here is a WT624..Under the extra welch plug is a very fine screen, no rubber pieces anywhere...the hole leads to the center of the venturi, before the other small holes that control the idle and mid range mixture...
The one I have here is a WT624..Under the extra welch plug is a very fine screen, no rubber pieces anywhere...the hole leads to the center of the venturi, before the other small holes that control the idle and mid range mixture...
#20
My Feedback: (19)
RE: WT 813 Syssa Carb Won't Pop
ORIGINAL: w8ye
Most of the people that jack the throttle a lot in a hover do not like the 813 because of the accelerator pump
Most of the people that jack the throttle a lot in a hover do not like the 813 because of the accelerator pump
My guess is that one of the main reasons the WT-813 was selected for the Syssa was that it was simply available and probably at the right price. Many Walbro carbs that will work for our engine applications are simply not available. Others may not be available in the right quantity or at the right price. Many carbs we use are long since discontinued and may only be available from old warehouse stocks .... which means limited quanities. Why Syssa chose the carb they did is just a guess though. This would be a good question for Mr. Syssa!
#21
Senior Member
Join Date: Jan 2002
Location: Arcen, , NETHERLANDS
Posts: 6,571
Likes: 0
Received 2 Likes
on
2 Posts
RE: WT 813 Syssa Carb Won't Pop
I checked many walbro carbs. My gauge goes to 40 lbs pressure. Sometimes that is even not enough, and the carb pops at about 50lbs. Still they work fine. Pop-off is not as critical as some know-betters want to make you believe. As long as the needle re-seats well, the engine will run satisfactory if the needles are tuned.
#24
Senior Member
My Feedback: (4)
Join Date: Jul 2002
Location: Somewhere,
DC
Posts: 9,825
Likes: 0
Received 0 Likes
on
0 Posts
RE: WT 813 Syssa Carb Won't Pop
The WT 813 was originally calibrated for a Zenoah G260 PUH helicopter engine.....The needles might be the finer thread mandated by the EPA so us mere mortals can't adjust the carbs easily...the fine thread needle carbs sometimes take 4 turns open to be right...Blame the EPA...Not the carb...
FWIW if you actually do a Google search on the Walbro aftermarket site you will see the needle thing on the first page....
FWIW if you actually do a Google search on the Walbro aftermarket site you will see the needle thing on the first page....