Power surging when hot

jrstone · Post by **jrstone** » Tue Jun 18, 2013 10:55 pm

I have searched the forum and google trying to find an answer and nothing has helped yet.

My '08 Buddy 150 has just over 2700 miles on it and just since the weather has gotten hot, I have found that after riding about 10 miles, the power will start surging when trying to maintain speeds of (indicated) 50-55 mph. It will accelerate fine until about 45 and will seem to bog down a bit.

-The battery was replaced about a month ago.
-Checked the air filter and it looks brand new still.
-Checked the spark plug and it looked OK but I replaced it anyway.
-I have gone through 3 tanks of fuel (with seafoam) since the issue started.
-The gas cap already has holes drilled in it.
-I did accidentally over fill the tank just after I got the scooter, but that was 2.5 months ago.

I am at a loss. It runs perfectly in the evening when the temps are lower, but when it's around 90 or higher during the day and the engine is hot the problem shows up. I have only had the scooter since April, so this is the first experience I've had with it in hot weather.

Any help would be appreciated.

agrogod · Post by **agrogod** » Tue Jun 18, 2013 11:18 pm

Could be fuel starvation. A bad fuel filter and/or fuel pump could be your culprit.

PeteH · Post by **PeteH** » Tue Jun 18, 2013 11:35 pm

150. No pump. But the filter is a good cheap replacement.

You could be looking at stator failure, and there are voltmeter tests around here somewhere, but replicating it at temperature will be tough, short of pulling the stator and heating it in an oven.

agrogod · Post by **agrogod** » Wed Jun 19, 2013 7:55 pm

Really? Not even a vacuum pump?

JohnKiniston · Post by **JohnKiniston** » Wed Jun 19, 2013 8:48 pm

The tank is above the carburetor. There is a vacuum operated fuel petcock but no fuel pump.

agrogod · Post by **agrogod** » Thu Jun 20, 2013 10:03 pm

Learn something new everyday. I'll tuck that info away.

jrstone · Post by **jrstone** » Mon Jun 24, 2013 4:01 pm

OK. Now I have another problem. We were out riding with friends and stopped to get some food. When we tried to ride off again, the buddy would not start with the electric start. Had to use the kickstart about 10 times before it fired up. After that it was not accelerating very well and would die if we came to a stop and the revs dropped. Took the battery in to have it tested and they said it was good, but had no charge. Since I had only had it a month, they swapped it for a new one. The buddy will start now with the electric start but will die if it idles for very long. Also, I noticed that the headlight will be quite a bit dimmer when it's idling and will get brighter when the engine revs.

Think that I have a bad stator, or is it something else?

TVB · Post by **TVB** » Mon Jun 24, 2013 8:00 pm

At least on the 50 it's not unusual for the headlight to dim while idling.