Honda Spree - sputter and bog at full throttle

[davids]

What its doing:
The scooter starts on the first try and idles great.  It accelerates smooth, but after a few blocks at top speed, it starts to sputter, bogs, and will die unless I let go of the throttle.   Once this happens, I can't run more than 5 mph or it dies.   If I shut it off for 20 minutes, the scoot will fire up, run great, but at full throttle it will die again after just 2-3 house lengths.   


About the scoot:
1987 Honda Spree
2,4xx miles
102 # compression
Ethanol free gas (only) & tank is clean as a whistle
New Battery
New Petcock
Had a full tune and carb overhaul at a shop 120 miles ago



Forum posts/tips that I tried:
NO LUCK -- Drained gas tank; lines; cleaned jets (I could see light shine through) and float; and used fresh fuel
NO LUCK -- After scoot warmed up, I disconnected the choke/auto enricher
NO LUCK -- Installed new spark plug and verified battery is charged (12.9V)
NO LUCK -- Cold start and full throttle has same result as allowing scoot to warm up, gentle throttle and cruise at only 20 mph


I'm looking forward to reading your suggestions....thanks!

-David S
 St. Augustine, FL

[gooddog]

maybe the carb slide needle doesn't have the clip attached which makes sure the needle goes up and down with the slide. if the carb was taken apart and cleaned they may have not assembled it correctly which may not allow you to accelerate after warm up. I am not sure if your compression is right. seems like it should be higher.

[spaz12]

Sounds to me like it might be running out of gas. Not because there's no fuel in the tank, but maybe the float isn't set right, a pinched fuel line, pinched vacuum line, air vent in the tank blocked, petcock not flowing enough or maybe the fuel filter. Those are some of the things I would look for.

Your compression, which I just noticed, is pretty low too and that could be your problem. Did you use a decent gauge to test it? Those Harbor Freight one's aren't so reliable.

[ryan_ott]

You may want to leak test the motor. A leak my be developing when it heats up and closes as it cools. But I'm with the fuel delivery idea.

[2stroked]

102 pounds sounds low for compression. Do a leak down test,and look in to getting the rings changed..,

[eclark5483]

My 86' Spree was doing the same thing, also had just a bit over 100 compression. When it doesn't have enough compression you won't get enough vacuum for the petcock to open like it should, thus it will starve for fuel when WOT. I'm also guessing rings are going bad. If your gonna change them, then go all out and do like I did and invest in a big bore kit. Tazland from the spree forums sells them on eBay: www.ebay.com/itm/Honda-Spree-NQ50-Elite-E-SB50-48mm-Big-Bore-kit-/371559461859

It's more expensive then a regular stock 41mm kit, but well worth it. The kit also comes with a #90 jet.

[davids]

May 22, 2016 14:34:09 GMT -5 eclark5483 said:

My 86' Spree was doing the same thing, also had just a bit over 100 compression. When it doesn't have enough compression you won't get enough vacuum for the petcock to open like it should, thus it will starve for fuel when WOT. I'm also guessing rings are going bad. If your gonna change them, then go all out and do like I did and invest in a big bore kit. Tazland from the spree forums sells them on eBay: www.ebay.com/itm/Honda-Spree-NQ50-Elite-E-SB50-48mm-Big-Bore-kit-/371559461859

It's more expensive then a regular stock 41mm kit, but well worth it. The kit also comes with a #90 jet.

awesome lil' kit!!!!  If I don't sell it, I may have to invest!