New Carb old troubles...

[99thwondah]

SOLVED...New Carb old troubles...

This engine is beating me down. Ordered new carb
http://http://www.ebay.com/itm/111366324837?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1497.l2649

Had to do slight modifications to get it to fit(enlarged mounting holes a mm or 2) Results...
1. Engine will run great only if choke is opened a little.
2. Fully closed choke it wont start.
3. Once running if choke is off it dies.
4. Hold throttle down starts first pull regardless of choke position runs then dies.
5. Idles good with choke slightly open.

I sprayed around carb for leaks didnt find any I'm stumped!! $99 for a Mikuni is Crazy since everyone who seems to have the Robin carb's go bad. Cleaned mikuni several times was hit and miss, Idle screw was broken off. So I ordered that carb.

Thinking only things I haven't adjusted are the valves? My gas maybe weak need higher octane/ seafoam engine? Cylinder and valves gunked? I'm out of ideas after these few, generator carb so circuits to different I figure any carb should work?.. When running engine doesn't smoke at all. 6.5 Robin by the way. Any and all suggestions welcomed

Motor is wonderful but before I buy 100 carb rather get a clone/predator cheap and plentiful parts/aftermarket support everywhere.

EDIT...

After playing with carbs and finally checking the valves to spec exhaust valve clearance was looser versus the intake valve. On the new Ey28 carb it has a return line to block off that I missed. Either way with both carbs engine couldn't FLOW to start easy and keep vacuum on idle, I would ride for a while and then no starts with old carb/new carb. Thanks to gran_pann for the governor mention/idle. Factory settings with Subaru's advanced timing system explains exhaust valve setting with governor. I remembered before removing it started easier,so I put exhaust valve a lil on the tight side of clearances. Starts right up now AND choke can be opened right after start up.

Any Robin Subaru 6.5 owners will be glad to hear that the EY28 Robin model is a close fit. Meaning you can make it work. Chinese knock-off available on ebay 30ish bucks runs a lil rich! Perhaps change jet! Thanks all.

 

[carter]

This engine is beating me down. Ordered new carb
http://http://www.ebay.com/itm/111366324837?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1497.l2649

Had to do slight modifications to get it to fit(enlarged mounting holes a mm or 2) Results...
1. Engine will run great only if choke is opened a little.
2. Fully closed choke it wont start.
3. Once running if choke is off it dies.
4. Hold throttle down starts first pull regardless of choke position runs then dies.
5. Idles good with choke slightly open.

I sprayed around carb for leaks didnt find any I'm stumped!! $99 for a Mikuni is Crazy since everyone who seems to have the Robin carb's go bad. Cleaned mikuni several times was hit and miss, Idle screw was broken off. So I ordered that carb.

Thinking only things I haven't adjusted are the valves? My gas maybe weak need higher octane/ seafoam engine? Cylinder and valves gunked? I'm out of ideas after these few, generator carb so circuits to different I figure any carb should work?.. When running engine doesn't smoke at all. 6.5 Robin by the way. Any and all suggestions welcomed

Motor is wonderful but before I buy 100 carb rather get a clone/predator cheap and plentiful parts/aftermarket support everywhere.

Re-clean the carb, but instead of just spraying carb cleaner, take a bit of wire and poke out the jet, often times you won't get it fully clean unless you do so. I think it's normal for an engine to not start on full choke, my engine starts first or second pull every time on half choke but it refuses to in full, I really don't think that's an issue.

 

[99thwondah]

The carb on it now is the new one clean as can be......

 

[landuse]

The carb on it now is the new one clean as can be......

Did you clean the old one properly with wire before mounting the new one?

 

[KartFab]

Thinking only things I haven't adjusted are the valves?

This sentence leads me to believe you have messed with things that shouldn't have been messed with. (e.g. did you mess with any of the throttle linkages or governor?)

Your symptoms, however seem to be carb/fuel delivery related. Yea your old carb may have been the problem, but what about your fuel line and gas tank? That could be full of gunk that just became trapped in your brand new carb.

http://youtu.be/XvHvxeiAdYQ

 

[99thwondah]

Im good with messing with things......governor is gone, custom linkage ,new tank with filter thinking its mechanical as in valves not breathing like they should can get it to run with both carbs still. Tolerance/deposits is what im checking next perhaps effecting tdc spark timing..

 

[KartFab]

Subaru engines have some magical timing system. I wouldn't mess with it. Look at their website for more info.

Also the governor controls an important part of idle believe it or not. You remove the governor, and you remove the engines ability to hold the throttle butterfly open upon start.

I believe all of your symptoms could be due to your governor removal/ and new throttle set up. I think there is still a fuel delivery problem. I can't tell you why it is happening though (throttle linkage messed up or carb getting gunked up, seal blocking an idle port who knows). Since you have messed with it so much I don't think anything else I know would help you. Good luck!

 

[99thwondah]

Yeah I read that they have advanced timing when it starts for easier starts .....never thought of that in reference to the governor wasn't connected on throttle though springs were rusted off...only thing im gonna try is perhaps seafoam cylinder than check valves to see if there in spec maybe loose from sitting for years and than running now. Soon as that choke is opened all the way that extra air kills engine or vice versa engine can't keep flow.

 

[Russ2251]

What you are describing is a lean condition.
Governor (or lack of it) will never produce this problem.
Possible valve problem but is HIGHLY unlikely.