I've been helping my brother with his 89 TRX350 (Dinosaur).
It quit running and we found that the fuel pump just quit working. We took it off and found that one of the contacts are worn completely down but we are still getting contact there. With the pump off and using aux power I can make the pump pull in and release by making and releasing contact with the power.
It appears that even though the worn contact is closing the circuit it is not releasing because the wear allows it to come up too high and therefore it will not drop back down and break the circuit. It gets very HOT when the key is left on because the coil is pulled in but never releases. I think I could make this pump work if I can build up some solder or some other metal on this worn contact but I'm thinking that it's not very likely.
Now I have multiple questions here;
Does anyone have any experience in doing such a repair and do you have any tips for me?

Is there an aftermarket fuel pump that can be used? I.E. low pressure fuel pump from autozone, napa, Orielly etc.....?

Where can I find the oem part for this machine?
Thanks,
Ron

 

I've tried fixing the contacts on one of those TRX350 pumps before. It worked for awhile, and then it quit again a few weeks later. If you want reliability, just put a new one in and be done with it. They're available from any Honda dealer as far as I know. They are also a little pricey as you might expect. I don't see why any regular low PSI pump wouldn't work, matter of fact I know of at least one person that has done so. Just depends if you want to figure out mounting plumbing it, of course the stock unit bolts right in perfect fit.

 

Thanks for the reply.
When you tried the repair did you build up the contact area with solder?
I would expect the pump from Honda to be pricey. I'll probably try the repair first and then buy one from an auto parts store. Any idea what the pressure for the stock pump is?

 

The few I've tried to fix (I've been a tech for 20 years full time) were corrosion problems. It was probably at least ten years ago. There is no pressure spec, but there may be a time\quantity test in the shop manual. I haven't found it useful to spend time doing it. Part of the tricky aspect of those pumps is that they don't run on 12VDC in the machine. There is a relay wired in to the pump power circuit that only allows the pump to receive voltage when the ignition is producing spark (machine is running) , or briefly when the key is turned on, so if you're carb is dry it will fill it up. One of the net effects of this relay is to cut back voltage to the pump. I've usually measured 4 to 7VDC on a known good working system. So...even if your pump works on battery type bench test, it doesn't mean it's going to work on the machine, at least not very well. And I've seen this many times. Often times you can get a pump that's "dead" in the machine to work fine on a good battery. When you put it back in it works OK for awhile (usually until the customer gets it home), and then dies again. I guess what I'm sayin' CaptRon...is do you wanna mess around with it indefinitely, get stranded out in the boonies, fix it repeatedly? Or just fix it right by replacing with new, be done with it and go out for a ride? Good Luck

 

Well as far as getting stuck......this machine never leaves the 35 acres that it is being used on so it will be a short walk if and when it does break down.
Now what I have found concerning power to the unit is that it seems to stay on any time the key is on. I found the fuel pump to be extremely hot when removing the fuel lines. The coil is staying engaged instead of engaging and releasing which is what appears to be the way it is meant to function.
Any idea what a new OEM pump would cost?

 

I actually got the pump to work for about 3 secs today. If I could replace just the relay on that thing it would work fine.

 

As I said earlier, your pump isn't supposed to have power simply with the ignition switch, the circuit is more complicated than that. The cut relay for the fuel pump system is located in the box underneath the right rear fender. If you do a search in these forums you'll see I've posted troubleshooting for this complete system. You can bypass the cut relay at it's coupler by shorting the correct two wires, thus allowing the full battery voltage to the pump at all times. Maybe that's what going on with yours, or the cut relay is simply shorted. Anyway, I've quizzed Honda tech services about this "amount of voltage" to the pump (Honda's motorcycle fuel pump circuits are similar). It was suggest to me that maybe the pumps aren't designed to work on the full battery voltage, and that running them that way over time (with the cut relay wires shorted) could damage them. As far as cost of a new pump, I'm guessing around 125$.

 

A correction from one of my earlier posts.
I said that it has power anytime the switch is on. This is incorrect. There is no power when the switch is turned on but once the engine is turned over the power is on and stays on until the key is switched off.

 

[img]i/expressions/face-icon-small-smile.gif[/img] hey dzzy your info is right on after replacing the fuel pump on a honda 1991 350 4x4 she is revived from the dead hats off to ya

 

Glad it helped.