suzuki DT 65 bogging with rpm

[Dunlop]

I have a DT 65, it idols and revs in nuetral fine.As soon us you put load on the engine it bogs out.I have cleaned the carbs and replaced the needle valves and spark plugs. Compression on both is 125psi. Spark on all cyl seems to be good and strong. I have tested to see if it is sucking air thought the seals or halves and it does not seem to be. I have replaced the feul pump ,hose and primer bulb aswell. Last year the water pump went and I had it replace,I also replaced the head gasket as I inspected the cyl and pistons. the power head got hot and melted the coating on the wires on top of the cyl aswell. If any one has any ideas what could be causing this bog it would be appreciated. thanks scotty221...

 

[JB]

Re: suzuki DT 65 bogging with rpm

Hi, Scotty.<br /><br />You are not runnning on all cylinders. What an engine will do when not under load is very misleading.<br /><br />Read some other threads on loss of power under load and try those trouble isolation techniques.<br /><br />Let us know what you find.

 

[Dunlop]

Re: suzuki DT 65 bogging with rpm

Hi JB. It seems to be running on all three all of the plugs are getting hot, and the test light is showing good spark. Where can I reed these threads. I was kind of wondering if the reeds could be weak or if there is a seal gone between the cyl. Would either of these cause this problem. thanks scotty221

 

[lakensea]

Re: suzuki DT 65 bogging with rpm

Check the ignition timing advance with a timing light. If you are not getting any advance, check the microswitch that is located on one of the carbs - use a continuity tester. That tells the CDI box when to advance the timing. If that is working properly and you still do nat have any timing advance when the switch activates you have a bad CDI box.

 

[manitoba1]

Re: suzuki DT 65 bogging with rpm

I had a 1985 DT55 which drove me crazy for some time which would run and start fine but would sometimes on acceleration would suddenly seem like it was running on one less cylinder. Most time it would run and accelerate fine. When the problem occured and I throttled back and re-accelerated usually the problem would go away. Eventually it became more frequent. It turned out that there is a water flow sensor in the powerhead (which is just a float switch) which activates the rev limiter in the event of low water flow in the power head and allows you to limp back to the dock if the impeller is going or the intake is partly plugged. My switch was sticking and acivated the limiter. If you overheaded the switch may have stuck and the limiter won't come off. The switch costs approx. $90 canadian and can be replaced in two minutes with a screwdriver. If I remember correctly it's on the rear upper right of that engine and has a single black wire coming off of it. Try unplugging the switch and see if it cures the problem. I see from you post that you are from Manitoba. I work in Winnipeg and have a Clymers manual (which would help with repairs) and spare prop for that engine if you are interested. I replaced my DT55 with a DF70 4 stroke. If you want call me at 235-3855 during the day and ask for Thane

 

[gonfishn]

Re: suzuki DT 65 bogging with rpm

I'm with JB on this one. I had the same problem. Neutral was fine but when I Put her in gear it would not rev. Turns out it was my top cylinder. It may be ok now but its only going to get worse like on vacation as with me. Mine is being fixed as I post. Its hard to find anyone near me who even works on them.

 

[Dunlop]

Re: suzuki DT 65 bogging with rpm

So far I think I am going with lakensea so far. The water flow sensor was replaced last fall and its not rev limiting its bogging. As for it not running on all cyl, all plugs are firing and compresion is good on all 3.

 

[Yepblaze]

Re: suzuki DT 65 bogging with rpm

Just an FYI I have a DT50 a couple of years older and had found out the hard way that the foam hood liner was deteriorating to a point where the bits were entering the float bowls. I would clean the carbs and it would be Ok for quite a few trips. Then it would get bits in the bowls, lose the main jet and bog out at full throttle again. This could happen from 30 seconds to 15 minutes into a trip out. Any attempt to remidy through process of elimination by raising the moteor or stoping to scratch my head would allow the microscopic foam bits to settle out of the jets and all would be good and well it they managed to find their way back in the jet. <br /><br />Removed old foam, and cleaned carb bowls and jets one last time and been good since.