Hi there! Just purchased a 1989 Honda Fourtrax 350. The previous owner told me that it has been sitting for about a year since it last ran and couldn't start it.

Anyways, this ATV is acting weird.

First of all, when I put the key in the ON position, the fan start spinning! I don't have any oil temp light coming on. Just the fan running.
If I try to start the ATV, I can't get fuel to the carb. If I pressurize the tank, I can get it to run for about a minute. Then it dies and unless I blow into the tank to pressurize it, it won't start.

So I checked the fuel pump. Didn't seem to work at all so I checked out the fuse: it was blown. Replaced it and tried to start it again: still no fuel and the fuel pump fuse blew. Even the main fuse blew during one attempt to start the atv.

Put new fuses and disconnect the pump relay. No fuse blew and got it to start by pressurizing the tank. Checked out the voltage at the battery: got over 21V!

So should I replace the voltage regulator? And is my pump / pump relay shorting something? Are they most likely dead? And why does it blow the main fuse too?

Thanks

 

If it is charging at 21v then yes, replace the regulator without delay. Years since I fitted a pump to one of these bikes, so can't remember much about it, but remove the wires to the pump and test it with a battery to see if it has shorted out, if it has, get a new pump. If it hasn't, check the relay and wiring for the pump. The fan coming on may be another electrical fault, or could be previous owner has set the fan to be on all the time, either to cure overheating, or because they didn't trust the temp sender to switch it on at the right temp. We maintain a few bikes where the owner has set the fan to run all the time. The fault in the pump circuit caused that fuse to blow, but the main one was getting massive ampage too, until the lesser fuse blew, that split second was enough to blow them both.

 

​​​​​Well, i have good news.

First, the voltage. Turned out that my multimeter battery was low and giving weird readings. Put a new battery in the multimeter and tested the battery and charging system voltage: all good!

The fuel pump is good too. Found out that the little screw holding the plastic cap was too long and shorting the entire pump, blowing fuses at the same time. So i replaced the screw by a shorter one and gave it 12V: the pump works.

Put new fuses, checked out the entire wiring harness. No melted wires, everything was okay.

The fan was fed by direct 12V from the ignition. Wired it back to the Fan control unit: oil light came on when turning the key. So far so good.

Final test, plugging back the pump and the fuel pump relay. Tried to start it: it started and the pump is working properly!

So that solves my fuel supply problem.

Now the engine ticking/chain noise.

Did an oil change. The oil was thin, liquid and black. The filter had quite a bit of metal shavings in it. Put new oil and tested: runs smooth. Except for the valve ticking noise at idle and the loose chain sound I get when I give it some throttle.

Removed the tensioner to check it out. Meanwhile my 5yo son came running and pressed the starter button for a second. Unfortunately I wasn't fast enough, it turned over. It obviously skipped a tooth because I put everything back in place but it doesn't start anymore.

Guess I'm gonna open the valve cover to investigate.