86 Suzuki DT-40 under load problems

[jtb8371]

I have a 1986 Suzuki DT-40 that is oil injected. I need some help figuring out what the problem is. When I took it out the other day it idled fine, but when I gave gas it would bog down and not accelerate and died a couple of times. I pulled it back up to the launch to check it out. I thought I may have had a plug fouled out. Pulled the plugs and found that neither of them were fouled out. The one in the top cylinder was wet with gas and oil but the bottom one was just perfect. Cranked it back up and it idled fine but there was a strong smell of gas. I found that there is a lot of unburned gas coming out of the exhaust. It will crank up good and idle good but won't run under load and has all that fuel coming out the exhaust.

 

[waffles1]

Re: 86 Suzuki DT-40 under load problems

Check thermostat. Believe it or not it can cause this. Also, I'd check the spark and compression on the cylinder that the plug was wet on first. It may just be a weak spark. Plugs are cheap, replace them if you haven't already.

 

[deejaycee_2000]

Re: 86 Suzuki DT-40 under load problems

DO you have good spark on all plugs?

 

[jtb8371]

Re: 86 Suzuki DT-40 under load problems

I will check the thermostat. That sounds like the cheapest fix. I know that it is firing but I'm not sure on how to check if it has a hot enough spark. Can that be checked with a multimeter.

 

[waffles1]

Re: 86 Suzuki DT-40 under load problems

Just compare the spark between the two plugs visually and see if you notice a difference. unless you have already done so I would go ahead and replace with new. I'd try that first before the thermostat. Good Luck!