1988 Suzuki DT85 rev limiter

[72INVADER90HP]

I have a 1988 Suzuki DT85. I it will run at 5500rpms at WOT then after 5 min die down to 2500rpms. If I let it sit for about 5-10 min it run at 5500rpms again. Now can anyone tell me ho to tell if I have a rev limiter on this motor?

 

[Matt_W]

Re: 1988 Suzuki DT85 rev limiter

Here is what my zuki manual says for the 1988 DT 75 and 85 model. Over rev warning system.<br />1. The over rev warning system is activated when the RPM reach 5900 +- 250 <br />2. The motor will exibit a misfire condition for 10 seconds and the rev limit warning light will come on if the customer continues to operate in this range.<br />3. After 10 seconds, engine RPM's will automatically drop to around 3000 RPM and the light will remain on.<br />4. The customer can prevent this drop in RPM by decelerating back into the recommended range withint the 10 second period.<br />5. If the engine RPM drops to arond 3000 RPM the customer must return the throttle to the idle position (below 3000 RPM) for one second to reset the system. At this point he can accelerate again back up to the recomended operating range. <br /><br />There is a graph that goes along with this and it shows the engine has a spark interruption system and a suzuki monitor rev. limit light. So to answer your question if it is an 1988 USA model yes there is a rev limitor.

 

[jim dozier]

Re: 1988 Suzuki DT85 rev limiter

You may just be losing a cylinder due to fuel or ignition issues. Make sure the enginge isn't overheating also. How do the spark plugs look?<br /><br />A couple of times my Suzuki DT85 has come out of the water on big waves at WOT and set off the rev limiter and it pretty much kills the engine completely for a few seconds. Scared the crap out of me the first time .

 

[manitoba1]

Re: 1988 Suzuki DT85 rev limiter

If the rev limiter kicks in when the engine hits big waves or for no particular reason it's more than likely the water flow sensor in the powerhead. It a small float switch which seems to get waterlogged over time. Had a 55 hp with this problem and drove me crazy until the mechanic replace that sensor. It activates the rev limiter to prevent overheading in the event there is blockage or not enough water flow within the engine.

 

[72INVADER90HP]

Re: 1988 Suzuki DT85 rev limiter

Thanks for yalls help. Nobody ever told me about the water flow sensor that is in the head. I checked my manuel and could not find it. I have rebuilt the carbs and the float levels were way off so I adjusted them and took the lower unit and took the water pump off to check the impeller and it looked great also checked the water pump housing for cracks and wear and it looked good. So I am down to desperation right now, where is the water flow sensor loctated at?

 

[rbowen]

Re: 1988 Suzuki DT85 rev limiter

It's located under the top plug on the Starboard side of the motor. Two screws hold it in and two wires connect it to the control box. It pulls out from the hole in the head and has a float on the end that raises and lowers as the water pumps into the head.

 

[72INVADER90HP]

Re: 1988 Suzuki DT85 rev limiter

Thanks I am going to look for it right now

 

[72INVADER90HP]

Re: 1988 Suzuki DT85 rev limiter

does anyone know how to check to see if that is the problem?

 

[jim dozier]

Re: 1988 Suzuki DT85 rev limiter

Disconnect it.