# 300 running wrong



## RHEEMO (Mar 14, 2012)

I have my 1991 Honda Fourtrax almost complete and was taking it for a quick test ride when i noticed the engine would bog down for no reason. If i hold the engine at about 2000 RPM, it will hold at 2000 for about 10 seconds, then suddenly bog down and the exhaust makes crackling sounds for a few seconds, then it will rev back up to 2000 RPM. it repeats this cycle over and over. It starts just fine and it will idle perfectly, it just has little hiccups every few seconds. Any ideas? The carb has been cleaned. Could it be the valves? I'm stumped.


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## mossyoak54 (Jan 16, 2012)

Might wanna check the fuel filter. Its easier the eliminate simple things first, also check the tank petcock and make sure it is flowing good.


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## RHEEMO (Mar 14, 2012)

I was just looking for the fuel filter, turns out i don't have one. Could that be causing this?


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## mossyoak54 (Jan 16, 2012)

Lol well if your running without a filter and anything has gotten in your tank, then its gotten in your carb. Id pull the line off the petcock on the tank and open it up and make sure fuel is flowing good, then id find a spot and install an inline fuel filter. Honda may have one in the tank i am not sure maybe someone will chime in that knows. Has it been sitting for a while?


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## RHEEMO (Mar 14, 2012)

It sat for 2 years before i got it a few weeks ago. Finally found a set of tires i could borrow to run it for a while. I cleaned the carb the day i got it. but the tank was bone dry. Maybe something got in the bowl from the gas loosening it up The petcock has a screen with a cup on the bottom of it, but I don't know its condition because every time i take apart a petcock i have to buy a new one because they start leaking. And they are stupidly expensive. I'll go get an inline filter just for good measure tomorrow and install it. Would you recommend using a fuel additive for it? I'll tear the carb out again and clean it one more time just to be sure after i get the filter on it. Thanks for the reply.


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## mossyoak54 (Jan 16, 2012)

Well one that has sat that long with a
Metal tank probably has trash built up
In it. Ill almost bet your problem Is not getting fuel from the tank. I'd still try to pull the line and see if it is flowing from petcock. 


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## mossyoak54 (Jan 16, 2012)

And as far as additives. I don't see why a little sea foam wouldn't help


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## RHEEMO (Mar 14, 2012)

I just got back from checking out the petcock. It flows fine, but i'll throw the filter on it when i pick one up tomorrow. gotta grab a can of carb cleaner anyhow. So, if the filter and carb cleaning don't help, what else could it be?


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## mossyoak54 (Jan 16, 2012)

Man I'm no honda expert but it just sounds like its not getting fuel. 


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## mossyoak54 (Jan 16, 2012)

The filter won't help it just needs one on it so trash from tank wont make it to carb. 


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## swampthing (May 2, 2010)

Do a spark plug test and observe it's condition. When you cleaned the carb, did you let it soak in cleaner or did you just spray it clean and reassemble? Did you change the high speed needle level? What condition is your air filter in? Will it run better without the air filter?.....


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## RHEEMO (Mar 14, 2012)

I soaked the jets in cleaner while i was cleaning out the rest of the carb. I didn't change anything about the carb other than the idle once i got it running. The air filter is terrible looking now that i think of it, but honestly it doesn't feel like a fuel problem, it feels like I'm slamming the brakes whenever it bogs down. It doesn't sputter like it's losing fuel during the bog down, It literally goes from 2000 RPM to maybe 200 in a split second, then right back to 2000 RPM just as fast.


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## Big Brute Force (Mar 4, 2010)

Where the little off and on and reserve is that comes off the gas tank. Turn it off and there is a nut on the bottom if I'm not mistaking, take a socket and turn it and the bottom will come off and I believe there is a filter in there


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## RHEEMO (Mar 14, 2012)

Cleaned the carb, in line fuel filter added, cleaned the little screen in the petcock, it would idle way better, but it still has the problem, re checked the vent lines and made double sure on everything. I'm stumped. Got the service manual and i'm going to try adjusting the valves tomorrow i hope. Thanks for the help so far guys.


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## mossyoak54 (Jan 16, 2012)

I would try like stated earlier and do a spark test. Lol I had a mentor one time tell me the basics to a running engine. Suck ,squeeze, bang,blow. If its doing all that right it will run. 


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## swampthing (May 2, 2010)

yep, gotta do a spark test to observe it's condition, but i'm leaning towards timing. Carb kit, sparkplug and new air filter would certainly help the situation as well.


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## RHEEMO (Mar 14, 2012)

Anyone got a basic routine for doing a spark test? Pull the plug, put it in the plug wire and hold it close to something metal, kick it over and see if it sparks? Or is there something special i have to do?


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## RHEEMO (Mar 14, 2012)

I just remembered, I don't have the battery in my bike. I've been testing it without having a battery connected to the bike at all. Could that be causing the problem?


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## mossyoak54 (Jan 16, 2012)

Yes definatly. Most of the time it will not run without it. Atleast my old honda 125 wouldnt


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## RHEEMO (Mar 14, 2012)

Cleaned the carb, new air filter, new spark plug, in-line fuel filter, valve adjustment, fresh gas. Still having the same problem. The petcock is messed up and only lets gas out of the tank if it is on reserve, would that cause it to not be getting enough fuel? I'm at wits end here.


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