1988 DT200 fuel pump question.

[R_Andersen]

I's still trying to find out why my 1988 DT 200 slows down and starts to die after running fine for a few minutes.<br /><br />I'm wondering how the fuel pumps are operated by the motor and how they should be mounted. I noticed the upper fuel pump on one motor seems to be loose. The mounting bolts are all tight but it is not being held tightly against the engine block. you can move it around slightly by hand very easilty. I saw there was an o-ring on the fuel pump that looks like it seals to the block so I'm assuming the pump should be tight against the block. <br /><br />I'm wondering if this pump being loose could cause it to not operate properly?<br /><br />Thanks for any advice,<br />Rob

 

[jim dozier]

Re: 1988 DT200 fuel pump question.

I don't know that specific engine but I'm going to go out on a limb and say you have a problem. I own a 1987 DT85 and I'm guessing the fuel pumps are probably similar,yours is just bigger and you have 2. Someone will correct me if I'm wrong. The fuel pumps work using a diaphragm and a couple of 1-way check valves using the vacuum/pressure pulses from the engine crankcase or transfer ports. Kinda of a suck in gas, blow out gas to the carbs thing. There should be an air tight seal at the O-ring where the pump pulls its vacuum/pressure pulse off of the block. Somethings amiss here. I would pull the pump and rebuild the diaphragm and O-ring and make sure it seats tightly against the block.

 

[R_Andersen]

Re: 1988 DT200 fuel pump question.

Yeah, that's what I was assuming. The problem is the fuel pumps are mounted on a rubber isolator with a metal sleeve in the center. When I tghten down the pump the bolt tightens up against the metal sleeve before the fuel pump is fully tightened against the block. I'll have to take another look at it this weekend and see if I'm missing something simple.....<br /><br />-Rob

 

[murphy1]

Re: 1988 DT200 fuel pump question.

On my 1987 DT200, the pumps are securly against the block. Since yours are loose, could they be sucking air?

 

[R_Andersen]

Re: 1988 DT200 fuel pump question.

Originally posted by murphy1:<br /> On my 1987 DT200, the pumps are securly against the block. Since yours are loose, could they be sucking air?

That was what I was thinking.... Now to find out why the one pump will not tighten down all the way?

 

[jim dozier]

Re: 1988 DT200 fuel pump question.

There's 2 pumps on that engine right? Compare the setup on the loose one to the other maybe somebody has put the wrong isolator or metal rings or something during a previous repair.