dt85 rpm problem

[rmac71]

I have a 1988 dt85 that will not go above 4000 rpms. I have cleaned carbs, replaced fuel line, quick connect and bubble. Replaced water pump, tach, and TPS checked out good. The motor runs good just will not go over 4K. The oil injection has been taken off and I am using premix. The motor had a 19 pitch prop and I changed to a 17 with same results. Compression test was 135/135/125.

 

[cornbread]

Re: dt85 rpm problem

have you checked the water pressure switch? my dt85 done that once before, the buzzer kept buzzin and wouldn't rev up.it was shuttin down i think 2 cylinders.give that a try.

 

[rmac71]

Re: dt85 rpm problem

I have inspected the water pressure switch it looked fine. The water light goes off a few seconds after start up. Also after I had the oil injection taken off the oil level light is still on the last green bar. Could this have anything to do with the RPM problem? If so how do I unhook it?

 

[rmac71]

Re: dt85 rpm problem

Any other ideas?

 

[cornbread]

Re: dt85 rpm problem

you could probably twist the wires together to by-pass it

 

[hookser1]

Re: dt85 rpm problem

The only way to check the flow switch is to remove it from the powerhead and check it for continuity. With the float in the lower position continuity should exist, in the upper position there should be no continuity. My fishing buddy bought a 91 dt85 and we just went through almost exactly what you have described. His flow switch was bad so we replaced it and it made the motor run smoother but still would not reach WOT. The previous owner removed the oil injection and hooked a female plug with 2 pink wires to another female plug with 2 black wires together with a small metal pin, when we noticed this we unplugged the the blacks from the pinks and now the motor screams. I'm not sure but I think the pinks went to the oil reservoir sensor and the blacks I'm sure are ground. Look for these wires on the left side if looking from the back of the motor.

 

[sk]

Re: dt85 rpm problem

any other ideas im in the same boat and have checked everything!!!!!!! Carbs, new fuel pump, fuel filter, fuel lines, oil pump and lines,....

 

[stylesabu]

Re: dt85 rpm problem

sk start your own thread. by the way there is a driveshaft that powers oil injection pump, and it uses the 2 stoke oil to keep it lubed.

 

[James R]

Re: dt85 rpm problem

If the drive shaft was not removed you will blow your motor!

 

[stylesabu]

Re: dt85 rpm problem

i thought that was implied when I stated that it gets its lube for 2 stroke oil that its supposed to be injecting. maybe it was that clear

 

[James R]

Re: dt85 rpm problem

You know that some guys don't understand the implied and it has to be spelled out. Just making sure there is no mistaking the issue. I have had several motors where the owner has failed to pull the shaft. Most recently a 150 Merc. What a mess. I managed to save it but only after replacing several bearings and going to 60 over on #2 where the gear securing bolt went.

 

[sk]

Re: dt85 rpm problem

sk start your own thread. by the way there is a driveshaft that powers oil injection pump, and it uses the 2 stoke oil to keep it lubed.

Where did i say i pulled my oil pump????????????

 

[James R]

Re: dt85 rpm problem

sk we repeat, please start your own thread.

 

[sk]

Re: dt85 rpm problem

sk we repeat, please start your own thread.

just having to much fun messing with you guys!!!!! i can reply to any post i want.....

 

[QC]

Re: dt85 rpm problem

Two year old thread. Closed.

sk,

You may think you can reply to any post you want, but I can delete any post I want . . . Please be respectful. The posters above were trying to help you, your own thread will allow focus. Thanks.