670 CC PREDATOR DOUBLE PULSE FUEL PUMP ! ! ! NOT

You will see a little gas on the first try but it is nowhere near the correct amount for the pump. This stems from a slit PVC or heater pipe, still looking for correct def on that. If this pipe is sound there is something else wrong . just another possible fuel issue. running without the filter on lessens the vacuum, so reducing the pulse on the PCV . Still getting my head around this, but the result is very a well running engine. I had been messing with it for 40 mins prior to the video, the wife said YOU SHOULD RECORD THIS incase others have the same issue... Voice of video on the pipe issue • PREDATOR670ccVOICE OVE...

[@mg-bx6bi]

Wish I could like this twice!! I'd viewed it before, but had forgotten. Searching for a solution ot no fuel flow and came across this again. Excellent expanation.

[@dctmakes3487]

Glad it helped ... Happy new year

[@jamesroberts9782]

My 670 was running fine. Engine shut off as I was working. No fuel to the carb. Thought the oil shutoff may have kicked in as it was down to the first line on the dipstick. Added oil to the second line as the manual says. Found out the low oil shuts down the spark. So watching your video i tried everything you tried with the diaphragm pump. You can see the pump diaphragm working on the center screen. Installed an electric fuel pump I had for a previous engine. Works great. Was working the engine and just like that smoke was blowing hard out the exhaust. Blue smoke like oil burning. All the hoses on the diaphragm pump are the same except for the intake and the output line. They are both just open. The big tube is back on the carb like it was. The PCV hose it connected to the old carb but the old carb is not hooked up. My suspicion is the crank case pressure is loading up because the PVC is not going back to the carb. What do you think and what do you suggest I do?

[@dctmakes3487]

Afternoon, trying to brake down you scenario. so firstly no electric fuel pumps on the base carb of the 670, its way to privative, meant for like lawn mowers or pressure washers no real proper idle. Get a new diaphragm pump, do what I did ensure the pump is pumping past the filter prior to the carb. (NOTE finger over the large line to the carb from the front of the crank case) turn it over is there sufficient fuel coming out of the pipe just before it enters the carb. Then work forward from there ... The electric pump caused so many issues you could not distinguish not enough fuel from flooding to no spark, oh yes a blue smoke like oil. Then check the carb solenoid is not messing you up, remove the slide pin in the carb. Then adjust the different jets (check the other videos) then punch out the welch plugs and even out the idle, once that's all done you can move on to main jet size for your situation and possibly remove/bypass the governor (depending on what your usage is)/// did you do a video on it ???

[@jamesroberts9782]

@@dctmakes3487 No, no video. Noticed the oil was way over full. Maybe because of the electric pump? It was fine before. I will get a new diaphragm pump and see what happens. I'm using it in a small Mustang Skid loader.

[@dctmakes3487]

@@jamesroberts9782 arh I see, yes my oil was thinned and raised on the stick as it flooded too many times. So for the use, you need to take the governor out of the picture, if its on pedal for power. not so bad if its more like a mower set the rev pattern and leave it. the jets will also come in to play, watch that video about the jets and exhaust. I have a vid re bench dry test with a fuel pump. this shows a 2 to 4 lb pump not pushing past the float BUT when yo add the draw from the engine things get very different and you get washed cylinder walls etc... if you can find a 1 to 1.5 lb (really that psi) its about the same as the diaphragm pump. also the location of the gas tank is important/ I have stories of 5 years of screw ups so let me know if this helps

[@dctmakes3487]

should say when you add the engine theres more vacuum/pressure in the carb, changing the pressure, almost like sucking on a straw

[@summitpressure9425]

Buddy I get it . I’ve been through 5 predator 670 My advise your missing a priming ball goin from gas line to 670

[@dctmakes3487]

cheers, I hear you, clutching straws trying to make it work the correct way, have a good day

[@jamesroberts9782]

PVC hose is hooked up to the old pump not the carburetor. Sorry.

[@stevieray1828]

How's the motor running with the pulse lines sorted out?

[@dctmakes3487]

Evening, working great, check the addition of the bulb kzbin.info/www/bejne/eZjKnImQqcupnNE , also the few vids pulling the wood around the yard

[@stevieray1828]

@@dctmakes3487 did you put a plug in that line to increase the pressure?

[@dctmakes3487]

@@stevieray1828 Evening, now thats a good question. No I just plugged it to prove the issue. I have it routed tp the carb plastic side were it came from. This along with putting the filter back on creates the back pressure. So moral is on these never try to fix carb issues with the filter off. Also ensuring that pipe is not split from the manufacturer like mine was. watch the voice over about that pipe in the early days...... kzbin.info/www/bejne/gZDdZp9jo8ehbLM

[@stevieray1828]

@@dctmakes3487 ok. I am trying a modification to create more pulse pressure...I simply pulled that hose off carb, put a piece of electrical tape on the male barb, poked a couple holes in it, and put the hose back on.... Hopefully the vinyl holds up

[@dctmakes3487]

@@stevieray1828 I guess easy to test .. pull the plug wires and unhook feed to the carb then turn it over, measure the flow/ when I blocked fully it was a drastic change as you saw in the vid. but I would say it will eventually pop the front and rear seals