1985 IH-385 with throttle trouble.

[CypressJeff]

Hello everyone. I have had this tractor for about a year with no issues up until 2 weeks ago. While running at higher idle (and probably under a load) the motor throttles down and then throttles up, over and over. Sometimes it stays throttled up for 10 seconds and then it starts going up and down again. I added some Sea Foam to the Diesel when it first started happening and everything worked fine for that days work. Now I am having issues again.

Today, I changed the 2 fuel filters and oil filter. I have a new air filter coming in on Monday. Any help would be appreciated.

 

[kwbretired]

You may want to check the rubber fuel line from tank, could be cracked and sucking air. When you have the fuel hose disconnected, see if fuel flows out of tank full flow. Also check the fuel cap to make sure the vent isn't plugged. Good luck.

 

[CypressJeff]

You may want to check the rubber fuel line from tank, could be cracked and sucking air. When you have the fuel hose disconnected, see if fuel flows out of tank full flow. Also check the fuel cap to make sure the vent isn't plugged. Good luck.

Thanks a ton for the help! I will put those 2 things on my list.

 

[CypressJeff]

So, i changed the oil. Changed fuel filters. Changed both air filters. I ran the tractor with the gas cap off and the tractor is still having trouble remaining at a constant rpm. I have not replaced rubber lines yet. I found the rubber lines connected to the injectors. Should I get them from any particular place? And out of curiosity, what do they do? This is my first time working on a diesel.

Does this sound like an injector problem?

 

[kwbretired]

The rubber lines coming off the injectors is a fuel return line I think. You can pick up fuel line at most auto parts store just know what size. Have you checked the fuel flow coming out of the tank yet, you could have trash or algae in the tank. Be sure all the air is removed after changing the fuel filter. You can pull off the line at the injection pump suction to see if you have good fuel flow. Having a full tank of fuel is also recommended when trying to purge air out of the fuel system.