Subaru/Robin EHO 35 help needed

Discussion in '4-Stroke Engines' started by Zev0, Apr 23, 2008.

  1. Zev0

    Zev0 Member

    Is anyone familiar with the Robin 35 EHO. Mine quits running when it gets warm. I think all it is, is that the idle needs to be pushed up just a tad. But I'll be darned if I can find an idle adjustment anyplace. Mixture screw I've found, but no idle. I've looked in the manual and it doesn't show one either. So, how would I up the idle a tad. In Phoenix here it gets really really warm. Well, actually HOT and I mean HOT

  2. fetor56

    fetor56 Guest

    A friend has an EHO35 so i'll ask him when he gets home from work but till then if noone answeres your question Zev the only thing i can think of is any idling adjustment is done via minor increases/decreaases in throttle cable tension.
  3. Zev0

    Zev0 Member

    That's what I was thinking also Fetor. Thanks. I really hope there is an idle adjustment screw tho. So much easier.
  4. ocscully

    ocscully Member Here is a link to the product page for the EH035 if you look to the right side of the page you will see links to downloadable versions of the various manuals for this engine. On page 14 of the Owners Manual it shows the location of the idle adjusting screw. It may be in the Service Manual as well but I didn't look that far.

  5. Zev0

    Zev0 Member

    Hmmm thanks OCScully. I have the manual and saw that. But if I give it like a 1/4 the engine starts smoking, so I just thought maybe in was the mixture adjustment. Turned it back down and smoking stopped. I dunno.
  6. graucho

    graucho Active Member

    Hi zev0, on my 035 I have the carb off half the time due to my hydro exp. But, that is the only idle adj that i know of. If I were to turn my idle screw 1/4 turn it would make the engine scream and then run ruff. I have to barely turn it to make it idle up. Is your air filter clean, and you have fresh gas? Oil full, so its not overheating? If the engine has sat for a long time run a teaspoon of seafoam along with a fresh tank of gas.

    Attached Files:

  7. Zev0

    Zev0 Member

    full of fresh gas, oil chg'd. What the heck is seafoam?? I have to go to the beach to get it?? LOL
  8. graucho

    graucho Active Member

    HeeHee, at the auto parts stores, at least in the upper states theres a great product I swear by. I could swear i saw it by you when I was visiting my folks. Here is a link with product specks. graucho___________air filter freshly cleaned?
    Last edited: Apr 23, 2008
  9. sparky

    sparky Active Member

    Yup, yup... North or South... Seafoam is loved by all. I've never seen an auto parts store that didn't push seafoam & lucas oil like crazy. They're both worth it.
  10. astring

    astring Member

    Did you ever get that worked out? what was the problem with it? I am super interested because I have one coming and I live here in the heat. Now I am running a Honda gx35 (close to the eho35) on a friction drive with no real problems. It seems like you got a defective unit because my 35cc 4 stroke zips along ok so far.
    Last edited: Jul 2, 2008
  11. az cra-z

    az cra-z Guest

    I noticed my R-S wants to stall out at idle now that it's really hot. I hold the throttle open a teeny bit when stopped (easy to do with a trigger throttle), or if it's a long stoplight I just let it die and restart when ready to move (very easy to do, need to open the throttle some as it tends to flood).
  12. astring

    astring Member

    Is it bogging down or only idling poorly?
  13. Torques

    Torques Guest

    In hot weather, just increase the idle screw to an acceptable rate, what's the big deal?
  14. astring

    astring Member

  15. Esteban

    Esteban Active Member

    Sounds like the carb just may be a bit dirty. With the quality of gas, these days, It can easily happen. " Seafoam " is a tinkerer's best friend.
  16. lowracer

    lowracer Member

    I had this same problem & tried a bunch of things before getting it figured out.
    The stock black fuel line that draws gas up from the tank to the engine is very easily crimped going thru the grommet & was restricting the gas flow at WOT when the engine got warm.
    I went to my ACE hardware store & bought some thicker clear fuel line and replaced the black one.
    Problem solved.
    Before solving the mystery, I drilled large holes in the black plastic air filter cover to allow more air flow, I found a gas station near a boat ramp that sells non-ethanol premium fuel, I cut off most of the engine shroud for better cooling at 30+ mph, inspected the spark plug for color & gap, played with oil levels & removed the black rubber doohicky under the gas gap for air venting.
    Hope this info helps someone.
    Engine runs out strong now...
  17. mbatl

    mbatl Guest

    With my R-S 35 on a FD setup, I can't go full throttle around the middle rpm range cause it will bog, but only at full throttle. Once near top speed, it can go full throttle though. I'm not sure if its overheating or something is wrong. It didn't do that the first month or so of ownership though.
  18. Richard H.

    Richard H. Member

    How's the plug look? Check your air filter, clean? The EHO35's have a felt and foam element. I remove the felt and oil the foam with 30W. The felt is really for extreme duty, industrial applications with a lot of dust.
  19. mbatl

    mbatl Guest

    Great advice, I haven't even thought to check the plug, its the original and I haven't had it to long, like 6 months maybe. I'll be sure to check the plug and the filter area.
  20. Nuttsy

    Nuttsy Member

    Next time this happens, reach back and loosen the gas cap a little. If the engine 'unbogs' take the gas cap apart and remove the rubber duckbill then snap it back together. These motors create a powerful suction that overwhelms that valve.