Only runs with fingers over carb intake

gliderbuff · Post by **gliderbuff** » Tue Sep 20, 2011 3:19 pm

I have to practically snuff out all the air out of the carb intake to be able to suck enough fuel into engine (literally choking it off) to make engine run.. and it is erratic at best. same warm or cold.. runs like shirt!

Any suggestions ... vacuum leaks reeds only 700 miles on 85 model Spree.... cleaned carb.

Bear45-70 · Post by **Bear45-70** » Tue Sep 20, 2011 3:31 pm

Can you say vacuum leak? And no, it is not the reeds themselves, could be the gasket though.

Trafficjamz · Post by **Trafficjamz** » Tue Sep 20, 2011 7:33 pm

Do you have the air box on?

no? Put it on

gliderbuff · Post by **gliderbuff** » Tue Sep 20, 2011 10:01 pm

Ok ... thats usually the case vacuum leaks... help me think this through... there are a couple "o" rings that mate the carb to the intake manifold, gaskets on the manifold could be leaking... main seals could be leaking how about air drawing in through the auto bystarter that seems to be faulty... needle doesn't move when electrical leads are touched to a 12 V power source. carburetor throttle spring cap... air leaking in there. How about the common leaks? anybody know of any that are going to occur during normal operation and use? Air screw set out 2 turns. Any troubleshooting ideas would be greatly appreciated.

Trafficjamz · Post by **Trafficjamz** » Tue Sep 20, 2011 10:16 pm

Trafficjamz wrote:Do you have the air box on?

no? Put it on

air box?

gliderbuff · Post by **gliderbuff** » Tue Sep 20, 2011 10:29 pm

Will not start with airbox on... so to answer you question ... the air box is not on.

Trafficjamz · Post by **Trafficjamz** » Tue Sep 20, 2011 10:43 pm

gliderbuff wrote:Will not start with airbox on... so to answer you question ... the air box is not on.

The spree will not run very well with the airbox off.

It should start and idle with no airbox ......but don't try to ride it with out one, it will bog out and stall.

You can look for other air leaks around the carb and intake where the vacuum hoses connect, that is a common place for leaks

Do you have to give it throttle as weel as put your fingers over the carb to start it?

If you do .....i would guess that your pilot jet is dirty. Did this moped sit around for a while?

Clean your carb

gliderbuff · Post by **gliderbuff** » Wed Sep 21, 2011 7:50 am

Good advise. Yes I need to give the scooter lots of throttle to make it run and it is erratic at best. The engine is always wanting to die... So today I plan to replace the rubber O rings either side of the block that separates the carb from the manifold. The carburetor body and jets have been soaking in a caustic carb cleaning solution over night and will reassemble them. Not sure what part the auto bistarter plays in all this but have ordered a new one and your advise about the airbox is good.. Will put it back on as soon as can make it run and idle without it in place.

So to review it takes lots of throttle and lots of choking manually to make her run. Put new fuel in it because yes it had been sitting around for some time .. only 700 miles on a 1985 Model Spree so clearly it has not been getting ridden.

Thanks for your suggestions...

Mystic · Post by **Mystic** » Wed Sep 21, 2011 10:23 am

have you checked compression? you may want to take the head off, spin the fan so the piston is at bottom and examine the cylinder walls if you dont have a way to test compression. you can be getting plenty of gas and good spark but if bad compression it will run erratically like you are describing

killerpancake · Post by **killerpancake** » Wed Sep 21, 2011 11:49 am

i agree with the above post, Many cases of hard to start mopeds i've dealt with lead to low compression. One of the cases was loose head bolts. never know till you pop that thing open.

gliderbuff · Post by **gliderbuff** » Wed Sep 21, 2011 7:49 pm

Good sound advise.. compression is good at 125psi. Which is a relief. After scratching everything I can scratch i went back to the first thing I checked on the motor scooter and that was the auto bystarter. I have two questions for the Honda engineers. What were they thinking and what were they thinking... old school guy that I am i just want a regular old choke.

Long story short by removing the auto bystarter (i even hate the name) plugging the hole that was left behind when I removed the thing a the scooter engine ran just fine.. I have ordered another one on ebay for $26 and hope I can put this thing on the road.

Most importantly I want to thank the folks here in the Forum who took an interest in this fun little scooter celebrating its 26th birthday.

Sincerely

Gliderbuff

Bear45-70 · Post by **Bear45-70** » Wed Sep 21, 2011 8:38 pm

gliderbuff wrote:Good sound advise.. compression is good at 125psi. Which is a relief. After scratching everything I can scratch i went back to the first thing I checked on the motor scooter and that was the auto bystarter. I have two questions for the Honda engineers. What were they thinking and what were they thinking... old school guy that I am i just want a regular old choke.

Long story short by removing the auto bystarter (i even hate the name) plugging the hole that was left behind when I removed the thing a the scooter engine ran just fine.. I have ordered another one on ebay for $26 and hope I can put this thing on the road.

Most importantly I want to thank the folks here in the Forum who took an interest in this fun little scooter celebrating its 26th birthday.

Sincerely

Gliderbuff

Real, old school chokes are inefficient for several reasons and is why they are now gone. They disrupt the air flow through the carb. Lowering carb efficiency, lowering power and mpg. So Honda did something that works well and causes very few issues. Normally when they do fail, they usually fail in the enriched mode (choke on). It is rare for the bystarter itself to fail in the close position, since the base position is open, needle retracted, extra fuel flowing when the engine is cranking or running. More often than bystarter system, if it supplies no fuel it is a plugged fuel passage between the float bowl and the bystarter chamber.

gliderbuff · Post by **gliderbuff** » Wed Sep 21, 2011 9:41 pm

Thanks for your input on the chokes... learn something every day... I hope this new Auto Bypass starter takes care of everything... thanks again for your interest in my post....

gliderbuff

Bear45-70 · Post by **Bear45-70** » Wed Sep 21, 2011 11:25 pm

gliderbuff wrote:Thanks for your input on the chokes... learn something every day... I hope this new Auto Bypass starter takes care of everything... thanks again for your interest in my post....

gliderbuff

Unless it was stuck in the extended position, it will not.

gliderbuff · Post by **gliderbuff** » Fri Sep 23, 2011 5:01 pm

Put in new By Starter thinking that would take care of things. Nope... still the only way it wants to run now is to remove By Starter completely and plug the hole. Only will go 25 mph top otherwise it runs ok... Somebody help me if they know.. Seems this will inrich the mixture. pouring raw fuel via the jet in the carb bowl up the siphon tube and into the carb venturi. That being the case then air is creeping in somewhere that i have been unable to find thus far. Compression is 125 psi. Any suggestions?

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Only runs with fingers over carb intake

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