Tuthill diesel pump problems

sodamo · Apr 23, 2014

Is there a relief valve? Remember reading some place the they sometimes cause a problem.

David Sent from my iPad Air using TractorByNet

Redneck in training · Apr 23, 2014

I also have the same or very similar pump. It primes easily 2.5 ft in diesel. The vanes are pushed out of the rotor by pressure in front of the vane through the groove. Therefore it is important to install the vanes in the rotor correctly. The groove has to be on high pressure side. Only thing I can think off is (assuming it has 12V DC motor) if the motor has permanent magnet stator polarity of applied power maters. Make sure it is rotation in correct direction.

Lothar Schmitz · Apr 23, 2014

Scott writes it is a cheap $100 pump, which tells me it is only a very small pump. The smaller vane pumps are, the more sensitive they are against internal clearances and 6 to 12 inches suction head is probably the maximum you can achieve with Diesel. As Scott writes when new and wetted with high viscosity gear oil it will prime a lot better.
Also the priming performance is heavily dependant on the rotor speed. The FR1612 pump has a 12 Volt DC motor. Check the battery voltage when the pump is running; it should be 12 Volt or slightly more. If lower, the rotor speed will be lower too.
When priming make sure the outlet pipework is open to atmosphere. Any restriction will lower the priming capability.
Lothar

jcummins · Apr 23, 2014

In my instance....low voltage was initially an issue. I corrected that, and it still did not prime, but perhaps that initial problem carried on even after corrected. I manually primed and the pump worked fine. Manually priming was messy. There is no relief valve. I bought this pump based upon many here on the forum using it, and I thought were happy with it. Perhaps losing the prime after each use is my issue.

Question...if I went to a 55 plastic barrel setup, so the pump would never lose it's prime, would lifting the diesel 3+ feet from the bottom of the barrel be an issue...IF it is primed. LBrown on this forum seems to have done that with great success, and it appears he is using the same pump. I was going to message him, but appears he has not been on the forum since November of last year.

Lothar Schmitz · Apr 23, 2014

I hope I understand your question correctly. If the internal parts of the pump and the suction hose remain filled with Diesel a vane pump of this kind should easily handle a lift of 20 feet and more. The discharge rate drops off very little up to 15 feet but from there onwards very rapidly. However your pump is limited by the power available from the electric DC current motor.
The answer to your question is yes 5 feet plus should be ok although at a reduced flow rate.
Just as a reminder; the suction lift is measured vertically from the liquid level in the barrel to the pump and not from the suction hose inlet at the bottom of the barrel.
I still believe if your blades are free to move in the rotor slots and the blade and rotor axial clearances in the pump housing are no more than say 0.001” to 0.002” your pump should prime Diesel at 5 feet plus.