1990 Suzuki DT 65 Throttle problems

Duggy08

Cadet
Joined
Jul 12, 2008
Messages
12
Hi, Ive recently posted a question on my Suz dt65 which will run fine for a few miles and then cut back the throttle to about 1/3rd revs. If you shut the engine off and restart it seems to run fine for a while and then die back again. The main suggestions I have had seem to point to overheating / faulty sensors. I have tried all sorts including changing fuel pump diaphram, cleaning out tell tale (which runs fine), changing plugs, checking filters, and most recently removing the float sensor and thermostat. The float sensor shows resistance on a meter when closed and none when open so I am assuming this is ok. Sounds like I know what Im talking about but this is all trial and error (with the help of a PDF manual) The thermostat opens up in hot water but never appears to close fully...is this normal. I have attached a photo to show it in a cold state.

Any more suggestions as to why the engine does this would be welcome.

Many thanks

dug
 

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BAO

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Joined
Aug 2, 2008
Messages
19
Re: 1990 Suzuki DT 65 Throttle problems

Hey dug I am looking at my t stat out of my 88 dt 65 and yours is not closing all the way. This I think would cause motor to run to cool I think
 

BAO

Cadet
Joined
Aug 2, 2008
Messages
19
Re: 1990 Suzuki DT 65 Throttle problems

I think what everyone is telling you is that there is a type of safety on these motors that will cut the rpms back so that you dont destroy your motor. This can be activated by low water flow, low oil flow, low oil level, or to high of rpms being reached. So really it could be any number of things. You said the telltale is working. Is there water coming out of the exhaust hole in the back?
Does yours have the gauge that tells oil flow water flow and oil level? PM me to talk further about this I will try to help.
 

James R

Commander
Joined
Feb 1, 2007
Messages
2,660
Re: 1990 Suzuki DT 65 Throttle problems

First I would throw that dirty old thermostat away and get a new one. Has this motor been used in salt water? If it has then you could be in for a rough ride.
Most important, if you are serious about fixing this motor then a manual is a must.
You could have an oil flow problem and the flow sensor is telling you.
You will need the manual to check the oil flow.
 

Duggy08

Cadet
Joined
Jul 12, 2008
Messages
12
Re: 1990 Suzuki DT 65 Throttle problems

Cheers for the replies. I have got a PDF manual, and have just ordered new oil folw sensor, t. sat and water float switch. Yes the boat has been run it salt water but gets flushes every time after use. There is exhaust water coming from the two vents at the rear of the unit and also from the prop.
not got my parts yet but will update in a couple of weeks when I get them back.

Cheers
 

ourhellhouse

Cadet
Joined
Sep 19, 2008
Messages
8
Re: 1990 Suzuki DT 65 Throttle problems

hi there i have a 1990 Dt 65 , does anyone know the spark plug gap ?
 
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