G1 Predator 670 Vtwin

[K.tran2103]

It was the spark plug. Rear cylinder was not working, replaced the spark plug and it ran great. Only thing was when I drained the oil, there seemed to be gas mixed into it. Also it’s Smokey when I initially start up but once I get going it’s fine. Any suggestion on what I should do next? My thought was from the cylinder it working it was spilling fuel back in.

Originally Posted by slonomo

Usually hard starting means the pilot jets are clogged. It's likely there are some tiny chunks of ice in there. I had the same thing happen to mine last week. Once it was fully warmed up it was fine. Shut it off overnight and it would be hard to start in the morning. Repeat. This cycle might cause the spark plugs to foul out. I pulled mine and checked them and sure enough they were coated black. Even though the plugs will fire, I couldn't get them to start the engine. After a thorough cleaning they will start the engine. I don't really trust these HF spark plugs, I'll be switching them out asap.

On a side note, I also had the same issue with my Vanguards and VC460. When the temps get below 25 degrees F, its a crapshoot whether or not it will start. Ether works, but I don't like that stuff, seen too many engines in pieces from it. I only use Ether as a last resort. Instead, I have a spray bottle with treated gasoline to start my equipment.

Another thought, make sure to treat your gasoline in the cans. There are several products on the market, just get one that treats it for storage and ethanol. The reason, warm fuel say 40 degrees F, can cause condensation to form inside the tank if the air temps drop rapidly overnight. The humidity in the air can cause a temperature difference inside the tank, this is what causes water vapors to condense. That condensation forms on the tank walls and ceiling, in turn dripping into the gasoline. This condition only happens when the air humidity levels are very high before the temperature drops. So it doesn't happen often, but it does happen. A small amount of water in the fuel is normal. Too much and it causes problems. If it freezes...you get "fuel line freeze up". One way to combat this is to keep the fuel level high in the tank, above 50%.

[slonomo]

Originally Posted by K.tran2103

It was the spark plug. Rear cylinder was not working, replaced the spark plug and it ran great. Only thing was when I drained the oil, there seemed to be gas mixed into it. Also it’s Smokey when I initially start up but once I get going it’s fine. Any suggestion on what I should do next? My thought was from the cylinder it working it was spilling fuel back in.

If you had gas in the oil it's likely from getting flooded when it wouldn't start. When the engine doesn't start the fuel in the cylinder can leak down past the rings. Gasoline also will clean the glaze off the cylinder walls and piston rings, that will cause it to smoke for a bit. Usually once you run it a while the glaze builds back up and the rings will seal better. If there is gas in the oil, the oil will be thinner too, which makes it seep past the rings causing smoke.

[K.tran2103]

Alright cool thanks. Also with that Vegas cart drop kit it gives the engine a slight tilt. Would y’all recommend trying to make the engine as flat as possible?

Originally Posted by slonomo

If you had gas in the oil it's likely from getting flooded when it wouldn't start. When the engine doesn't start the fuel in the cylinder can leak down past the rings. Gasoline also will clean the glaze off the cylinder walls and piston rings, that will cause it to smoke for a bit. Usually once you run it a while the glaze builds back up and the rings will seal better. If there is gas in the oil, the oil will be thinner too, which makes it seep past the rings causing smoke.

[slonomo]

Originally Posted by K.tran2103

Alright cool thanks. Also with that Vegas cart drop kit it gives the engine a slight tilt. Would y’all recommend trying to make the engine as flat as possible?

I usually fabricate my own mounts so they sit level. If it's just a couple degrees off it shouldn't matter. If it's a strong angle you'll want to correct it. I've seen people use washers as shims under the engine on one end.

[slonomo]

Yesterday I put some time using the G1 and ran into an issue. It would run long enough to drain the bowl then stall. If I let it sit for a minute and restart, it would run fine at idle. As soon as I drove the cart it would stall within 50 feet. Let it sit, restart, repeat. Talk about FRUSTRATING!!!

So, off came the carb. I full disassembled the carb again, this time removing all of the jets and spraying them out thoroughly, which I though I did once already lol.

I put down some clean white towels and let the carb spray drip onto the towels. I was amazed! Metal shavings all over the place!!! I looked into the deep reaches of the carb and noticed metal shavings/burrs on almost every machined and threaded hole. Using a small tool I deburred every one I could see and get to. Some big shavings came loose.

Ahhh Chinese quality manufacturing.

[slonomo]

Since I'm not a big fan of Chinese small parts, I decided to check all the little parts in the fuel system. I discovered a filter in the vacuum pulse line. I took it off and opened it up....what the.... It has some stainless steel shavings like what you'd see in some kitchen pot scrubbers. WTH??? Also inside was some kind of gritty plastic biscuit thing that literally disintegrated into tiny little pieces. I just took all that crap out of there and used a piece of rubber fuel line with no obstructions.

On a side note, the piece of fuel line I used in the photo was too short and I ended up cutting a new piece. The line has to thread through a metal bracket for the fuel pump.

[slonomo]

I also took the liberty of checking the fuel pump. I pumped fuel into an empty water bottle so I could see the fuel volume and pressure. After 15 seconds of cranking I only had about 1 oz of fuel and the fuel just dribbled out without much pressure.

I yanked the Chinese fuel pump and replaced it with a Briggs Mikuni from my 16 Vanguard. It was identical in dimensions and bolted right in without modification.

You don't have to take the engine shroud off to remove the fuel pump, only the air filter housing. There is one 8mm bolt holding the fuel pump bracket in.

The result? Soooo much better!!! Twice as much volume and pressure, I couldn't believe it.

[slonomo]

After tuning the carb it was running better than ever. When I tuned the two pilot circuits I started with the screws 2 turns out, ran the engine at 3000 rpm to warm it up. I used a laser thermometer to monitor engine and exhaust temperature.

On this engine the right side main jet is 108 and the left is 105, so I paid attention to the exhaust pipe temp to get the jetting balanced. I've never done one this way but read about it so I thought I'd give it a try. The idea is that a leaner air/fuel mix will be hotter than a rich one. So the goal was to tune the pilot jetting by sound and feel then adjust to balance the the exhaust temps. It actually worked quite well. The area of the exhaust pipe I checked was about 1" from the exhaust flange on the topside. Temps were fluctuating but were maxing out at about 570 degrees F. Surprisingly I could see the temps change with every 1/4 turn of the pilot screw.

Now the cart will idle smooth, has immediate response off idle, good seat of the pants power feel, and good acceleration. No hesitation, no bogging, no stalling. And guess what? It doesn't run the fuel bowl dry

[slonomo]

The next issue to tackle is the tachometer. The Equus tach doesn't not like this 670. It worked perfectly on the 440/460, the 16 and 23 Vanguard. Now the tach needle jumps all over but most of the time doesn't register. Pretty bummed about this.

[PharmGuy85]

Originally Posted by slonomo

The next issue to tackle is the tachometer. The Equus tach doesn't not like this 670. It worked perfectly on the 440/460, the 16 and 23 Vanguard. Now the tach needle jumps all over but most of the time doesn't register. Pretty bummed about this.

Have you read the Vegas Carts tach install guide. The mention that even their tach has issues with the 670 and that ordering a different set of ignition coils seems to fix this issue. I just ordered a set off Amazon.