# Echo Primer Bulb Prob. Need Help



## tperk100

Have an Echo Trimmer/Brushcutter Mod# SRM-230 Ser# 05165131. 

The (new) Primer Bulb does not fill when activated. There are three lines out of the gas tank. I am not certain what the one does the seems to simply go to atmosphere. It seems like it might have a check valve on the atmosphere end.....not sure. Is this a vent?

Anyway I took the other 2 lines that connect to the carb out of the gas tank. I suppose one is a return and the other a supply.

When I clamp off both of these lines, the primer bulb will not depress. This seems good to me. 

However, if I depress the primer bulb, hold it that way, and THEN clamp off the 2 lines, and then release the pressure off of the primer bulb, the primer bulb pops right out.....retains no vacuum whatsoever. Think my carb could be screwed up?

Any suggestions will be appreciated.


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## paulr44

The primer isn't a primer at all, it is an air purge for the carburetor system.
Yes, the little white thing hanging out in space is a tank vent - supposed to let air in, and not out.
When you pinch off the fuel lines and let up on the primer, on the return of the bulb is emptying what fuel it can from the metering chamber...it is natural for it to return a couple-three times before it creates a partial vacuum.

If a carb.-mounted primer doesn't fill, it could be the primer plate is NG.
Clamping off both lines an pumping the primer isn't a test we use. Clamping one line off at a time and pumping it does help tell you the condition of the primer check valves.

Sometimes a primer won't fill, but the engine will still run ok - rare, but it happens.
In most cases when a primer won't fill, there is crap in the fuel system - clogged filter in tank, clogged inlet screen in carb., or stuck inlet needle valve. Or just heavy corrosion in the carb.
A bad carb. fuel pump diaphragm check valve (flap valve) could also provide that symptom.


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## tperk100

So Paul, what would you suggest I do next?

Thanks much!


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## paulr44

Usually when the conditions I mention above exist with regard to a restriction in the system, the primer won't prime and won't return either. Still, they have to be checked to be eliminated from suspicion.

The fuel filter will need to be replaced no matter what, because if you end up replacing the carb., you should always replace the filter to protect that investment.

If it still doesn't prime with a new, or without a filter (can test w/o one to speed things up here), pull the pump chamber cover - the side opposite the primer. There's a screen in there, and 2 flap valves that would then need inspection. FYI rarely you'll have to take note that the screen inlet is reverse flow, and crap can be under the screen rather than on top. Depends on the specific carb. If you ever pull one out, you'll need a drift punch or similar tool to re-insert properly.

If the screen and flap valves look ok, pull the metering chamber cover with the primer over it. Check the inlet needle valve to see if it can be opened freely by depressing the lever. If so, then that would just leave the primer assy. as the potential problem.

While this may be a learning experience, you have to consider WHY the primer quit to begin with...usually it's from stale fuel building up gum/varnish, or corrosion, both of which are from not using a fuel preservative. And if you find gelled fuel, stop there, that's bad news. Given how much time and money you could spend trying to get it to work properly, and that small delivery galleries could remain restricted and it still won't run right even once the primer works, your best bet is then to replace the carb.

In other words, after the new or no-filter prime test and pump side inspection, if you have nothing definitive I'd just replace the whole carb. Guaranteed results if the rest of the engine is in good shape, and a lot less frustration.

I don't just tell people to replace carbs. as that's the easy route, I've rebuilt any number of carbs. with less than adequate results, or no improvement at all. Small passageways can remain clogged/restricted even after ultrasonic cleaning, nozzle check valves fail, and it just ends up being a loser. If the carb. is under $75, I don't even try to rebuild it. BUT, finding out WHY it failed is important - so you can fix it, and so you can prevent it from recurring - the carb. is usually the symptom, not the disease. An intake vacuum leak can mimic carb. problems for instance, but throwing a carb. at it won't cure it.

FYI your carb., RB-K70A (the RB-66 subs to the 70) can be had for less than $70, and an aftermarket one can be had for less than $20.


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## 30yearTech

In addition to the fine points Paul makes, I have also found that Echo units seem to develop leaks in the fuel delivery line. This can allow air to enter from the fuel fuel line and render the purge pump inoperative and cause the unit not to run properly. 

Make sure there are no leaks in the fuel delivery line from tank to carburetor.


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## tperk100

Paul and 30,

What i omitted in my OP is that I had already taken the carb apart and tried to clean it. The unit was priming and running before I did this but had a very difficult time accelerating, would shut off most times, and would stall at idle. To get it to run even close to reliably I had to leave it partially choked. After reassembly and then confirming that I had correctly assembled it, the primer would not pump fuel, so apparently I turned poor performance into NO performance.

I have decided to take what I hope is the easy way out. I have ordered a new carb

http://www.amazon.com/gp/product/B001OKBI92?psc=1&redirect=true&ref_=oh_aui_detailpage_o00_s00

for $20 from Amazon that has 100% positive reviews (only 4 though). I also ordered a Fuel line Kit with filter and vent, and a new intake gasket.

I have been using Trufuel for the last couple of years, but the machine has not been running correctly. The carb is about 10 yrs old. I should be good to go from here for a long time.

Thanks much for your help.


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## paulr44

There's Trufuel, SEF etc. out there, I use Redmax canned mix exclusively in my trimmer, and it starts 2nd pull every Spring. What's good about canned fuel besides the long storage capability, is that the diaphragms don't dry out. I've seen some issues with other than OEM canned fuels, you may want to try Echo brand, or Stihl or Redmax for example. They will cost you more.


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## Tony_D

Hi all, new the forum and first post.
Sorry to hijack your thread but the reason I joined this site is I'm having a problem with my Mantis tiller. Its about 15 years old and the last few years I've had to put a kit in the carb to get it to run. I only use it twice in the spring to till my garden and every 4 years to dethatch my lawn. (I started using pre-mix fuel a couple years ago.)
So this year it wouldn't run even with a kit so I decided to replace the carb.
New one, out of the box, prime button works, starts on the second pull, till the garden and dethatch the lawn with no problems.
Two weeks later I go to use it again and the primer didn't fill. I pulled the primer off and blew in the ports, ran a small wire thru etc.
Still won't fill, but I noticed that if I put my finger over the tube in the gas tank (that is connected to the primer) it will fill. But now I notice bubbles in the primer bulb. Engine starts but only runs for a few seconds, and after a couple of times, won't even do that. I pulled the spark plug and its wet. After drying it, it only runs a few seconds again.
I'm going to replace the plug next but any ideas? Did I damage the primer by poking a wire in it? What would make it run rich (if the new plug doesn't resolve the problem)? Ignition module going bad?
Thanks!


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## tperk100

Tony, you should start another topic / thread.

GUYS....CASE CLOSED....the new $20 carb fixed the problem! Thanks for your help.


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