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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. But he told me that it was working perfectly before he parked it in the garage last year.

Long story short, when I came home, I realized that I paid way to much for this.

130psi compression
No start unless I pressurize the tank
Horrible ticking/metal noise in the top end. Sounds like the chain is going all over

Anyways, I want it to work so here's my issues.

First of all, when I put the key in the ON position, the fan starts running! I don't have any oil temp light coming on. Just the fan running at full speed.

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 unless I blow into the tank again to pressurize it.

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 disconnected 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? I will check out the relay and pump tomorrow but sounds like there's something going on with the fan control module too.

Thanks
 

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Download the service manual and check parts links in my signature block below. Carefully check part numbers for your model year using the parts links—lots of parts are same but many are not interchangeable. Only buy OEM if possible beware many sellers will mislead you on these parts.
Diagnostics for oil temp sensor page 20-4 I think—you might have the oil temp sensor wire broken off and shorting but you’d see an oil light too. Maybe bad FCU. Maybe bad dash light.
You got a project alright, but you’ll do OK. Buy OEM fuel pump for starters-about $150.
To set the valves you’ll be surprised how much stuff you have to remove. Mght want to check the cam chain stretch and perhaps change it while you got it stripped down.

get a can of deep creep penetrating oil and spray every bolt you see. Careful when removing bolts—use the best 6-pt sockets you have and a couple diff size breaker handles. very gradually apply torque to loosen
 

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Discussion Starter #3
Thanks for the reply Goober. Tomorrow I'll check out if I can get the pump to work by giving it direct 12V. Then I'll check the wiring. And thanks for the service manual, I'll check this out.
 

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Thanks for the reply Goober. Tomorrow I'll check out if I can get the pump to work by giving it direct 12V. Then I'll check the wiring. And thanks for the service manual, I'll check this out.
start with an oem fuel pump..do not buy those stupid china knock-off pumps from ebay !. cam chain needs replacing. fan is coming on maybe because the PO hot wired it straight to 12 volts to run all the time with the ignition switch on ?, or the fan control unit is bad ?. deff a bad reg/rec !. fuel pump cut-off relay sounds bad. 130 psi is way to low to run, noise can be anything from the top end messed up ?. i would say you have your hands full for sure !. getting parts for this model will be very hard to locate, some you can get from honda ( fuel pump and fuel cut-off relay ) others are used on ebay, or a salvage yard. i know the reg/rec is discontinued from honda, as well as the fan control unit. with the fuses blowing like you claim ?, and the high voltage ?, my money says the reg/rec is bad ?, or you have a short some where in the wire harness ?.
 
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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!
 

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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!
haha..make your 5 yrd fix it !...lmao. you may as well look for a D.I.D. cam chain, clutch cover side gasket, centrifugal clutch puller tool, 22mm deep socket, air impact gun, and a tube of yamabond or hondabond...DO NOT USE RTV SEALANT ON THE ROCKER BOX !!!!!!. while you have the clutch side cover off, pull the oil pump pick up filter screen, inspect/clean it, put it back in !.
 

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Get a box of ziplock bags and index cards; and some large empty boxes. Take pictures of the parts you’re removing. When you remove a part, bag the part and hardware and write down the part name on the card and stick it in the bag. Put the bag in the box. This helps you put the right size bolt back where it belongs. The parts you remove last will be on top of the pile!
Get some antiseize compound for those bolt threads.
Hmmm now for your kid to turn over the engine he had to turn on the ignition....lol
 

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Hmmm now for your kid to turn over the engine he had to turn on the ignition....lol
Yup my mistake... i'm the one who showed him how to turn the key and press the button.. I take all the blame anyways 😅

Thanks for the advice goober, it will be less headache than trying to figure out what part and what bolt goes where... Too bad its not like my Stihl KM130 I tore down last week.. All the same bolts, you can tear down the whole engine using only one tool!
 

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Haha that will show him!

Thanks for your advice shadetree, and thanks for all the help you give to people here in the forums! Very appreciated to have knowledgable people helping us!! 👍
you are welcome, i love helping ppl save money on repairs !, been doing this for 29 yrs, i consider myself pretty good at what i do ? :). me, and others have went to our own site we built, you can find me, and other smart members here --> www.atvhonda.com
 

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you are welcome, i love helping ppl save money on repairs !, been doing this for 29 yrs, i consider myself pretty good at what i do ? :). me, and others have went to our own site we built, you can find me, and other smart members here --> www.atvhonda.com
Good, thanks for the info. I'll see you guys there!
 

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