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2016/06/01 16:17:35
SBlake

Ryobi 4 Cycle Trimmer Run Issue

Couldn't get the unit to operating rpm's.  Replaced the in and out gas lines and fuel filter. Still couldn't get it to operational speed.  Replaced the carburetor with a new unit from Jack's; however, it now only operates at idle with full choke applied.  Think it might be the fuel mixture adjustment.  Any support of this assessment or other recommendations?  Thanks SBlake 
10 comments Leave a comment
Mikel1
That's what I would try to do since a new carb.
2016/06/05 12:40:46
MdStamen
 I am not sure what carb you have. It may be the idle stop screw. That stop adjusts the position of the idle jet for idle. If it only runs with the choke in idle it is starving. Turn the screw in a few turns and see if it will run without the choke. As the throttle turns it lifts the jet.
I always check the intake and exhaust valves for the proper setting.
Before you worry about high speed you need to get the idle fixed first!
2017/10/06 07:54:51
AVB
Really need the model number to see what the setup is.
 
But from my experience with the Ryobi and Troy-bilt 4 cyclers it not worth trying to fix them as they tend to destroy the piston and cylinder due to lack of proper oiling. A very poor design when it comes oiling. I only get about one out twenty to work once they start giving problems.
 
 
2017/10/06 13:31:19
vmax1200
Make sure your fuel cap isn't causing an issue. Check the exhaust port and muffler. Make sure they're not restricted. And I agree, it definitely sounds like fuel starvation. And make sure you have the fuel lines on the right connectors. I would say you probably need a carb adjustment, but since you already replaced it, you should have noticed a difference. Might not have run perfect without a little tweaking but usually a noticeable difference.
2017/10/08 15:48:53
MdStamen
And if it is a 430 R. They are a beezer to get started. And I dis-agree. Yes 4 cycle engines may have problems when they are ran in some positions too long. But they can be repaired easily.Unless the engine is locked up.
BUT, I have a 990R 20 years old and still kicking. It is just impossible to get parts for.
The 430 has a strange Ruixing. You can but the carb , but not the kit.
Although Jacks has a excellent price for the carb.
2017/10/11 18:21:15
MdStamen
I have said this a lot. You have a cracked air dam. Some call it a manifold block.
And Jacks has a kit which will work on the s430 it is:

Stens 615741 OEM CARBURETOR KIT.

Just match up your gaskets first. You will need a Walbro tool to set the float level.
But for a little more buy the new carburetor.
 
2017/12/05 13:54:57
AVB
MdStamen And I dis-agree. Yes 4 cycle engines may have problems when they are ran in some positions too long. But they can be repaired easily. Unless the engine is locked up.

Then you haven't seen the damage I have seen on the newer ones. Once they start blowing oil through the PVC vent it is all she wrote; unless, you like short blocking for free or nearly free labor. There is a a lot of work disassembling and reassembly just to get one working again. A half day at least when you know what your doing.I don't even brother any more if when I drop the air cleaner and it is full of oil. These engines were never locked up but still never would run; unless, short blocked.
 
Or try replacing a timing belt on half shaft design for you must disassemble the crankshaft by pressing it apart. Some newer designs are using gear driven system but once one of the arms that drives the push rods breaks, again it is a short block time.
 
Once the rings and cylinder are damage there is no rebuild parts except for a short block.
 
I just got done sending a half a pickup truck load to the recycler.
 
Now repairing a carburetor is child's play and when it is a Walbro or Zama cube or rotary using OEM parts which I can get less than the Stens kits. Even some of the Ruixing carbs are repairable if you know which Zama gaskets and diaphragms will work as many of the Ruixings are Zama clones. BTW the Walbro W tool will not work on all the the Walbro cubes and rotary carbs. The WTE is good example of this where the tool is off by .039"
 
For buying complete carbs be extra carefully getting them off Ebay as some are rejects that some just on unsuspecting buyers. Even new replacement Ruixing carbs may need to be rework just to get the engine to work correctly. I know of at least two Ryobi blowers here that I had to modify the choke vane just to get them to stop flooding at start-up.
2017/12/05 14:36:33
MdStamen
BTW the 430R does not have a air foam filter. They use a screen. I was wondering if the assembly from the new full crank 2 cycle units will work? It looks like it would in the diagrams. Maybe add a hole for the breather.Or maybe the engine will not run properly with a foam filter.
I just was wondering why Ryobi did not add a foam filter!
2017/12/14 02:29:11
Roy
Cost. I was shocked when I saw that but the theory is the powerhead is high enough that it isn't really necessary. Realistically, the unit will probably crater before it wears out from dust ingestion
2017/12/14 11:18:05
AVB
As Roy said cost. A half penny here and there adds up when you're building thousands of these. Just look at what Briggs wants for one the foam carburetor seals.
 
I heard of trimmers several years that were using just screen wire filters. At that the manufactures claim that anything that made it the screen would not hurt the engine. I don't believe it as I have what dusty dirt can do to engine's cylinder not mentioning small pieces sticks.
 
My vendor did real life test on one and even screen was showing wear within 10 hrs.
 
As I said before the only 4 cycle handhelds that I know to work well is the Stihl 4-mix models.
2017/12/14 12:51:20

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