An open forum for all enthusiasts of the classic 60 series Nissan Datsun Patrol to gather and share information and gain knowledge. Members share off-road stories, restoration advice, modification ideas in an atmosphere free of a single controller. The fo
Won't run? Engine, cooling system, fuel pump, carb, clutch, tranny, brakes, etc. The old messages from the NPCA 'Engine & Mechanical' category are here.
I have a feeling I should start at ground zero at this point. I have wasted so much time thus far and made it not better but worse in a different way than when I started.
Reading from the Nissan Engine Model P Service Manual does not get enough info for me.
I would like to know how to adjust my idle lower but not have it die when I come to a stop.
I may have to take it apart and start by gauging the fuel level and adjusting that first but want to shortcut because I think it is still fine from a rebuild not too many miles ago.
At first the problem was idling too high. I tried the directions on pg 84 but they are vague. The combo of turning the screws is inconsistent. I now have a lower idle but it still stalls on stopping and now backfires a higher speeds when I let off the gas quick.
For me this was the best carburetor that was fitted on a Patrol. Maybe not the one that you can extract the most power, but very stable. It has a nice feature, with the main jet easily accessible from the outside. I used to live at 9000 feet above sea level, and lowered the main jet to 125 from the standard 138. When it was time to go to the beach, I will stop at the side of the road, and change back to the 138 to prevent piston knocking at sea level. Going back, reverse the process.
From your pictures, the fuel level is way, way to low. It should be between the two markings on the sight glass tube. All the problems you mentioned are related to it. You're getting too lean a mixture in some instances, and that's very explosive.
I will correct it, and then follow with further troubleshooting.
Adjust the idle with the screw that appears on the second photo.
Turn the air adjusting screw until the engine starts to hesitate a bit, and go back half a turn.
Reset the idle speed again.
Agree with Esteban- the fuel level looks too low in the sight glass- I would bet that if you check the inverted float level it would be more than the 20-22 mm that the manual calls for.
If you check it and the float level is within specs, then your fuel filter might be clogging up, or your pump might be getting weak (you have an electic fuel pump, right?)
I love the fact that the Hitachis have that sight glass- very cool feature- I wish the Rochester B carbs had something similar.
When braking, inertia carries the fuel forward in the bowl - if the port from the bowl to the main jet and venturi loses its fuel feed during braking, then the engine's going to stumble and possibly stall. Having a lower than normal fuel level in the bowl would only intensify this situation. LIkewise, if the fuel level is too HIGH in the bowl, then braking can cause raw fuel to spill into the throat of the carb, which can also choke out the engine (which would be noticeable by an accompanied black puff of smoke out the exhaust pipe)
If the carb was recently rebuilt , then you should be able to carefully take the top assembly off it it without tearing any gaskets - then you can turn it over and check that float measurement. It should be 20 to 22 mm WITH the gasket in place.
Another thing to look at while the top is off is to make sure that all the holes in the gaskets line up correctly with the ports in the carb body- I 've noticed many times that with the gaskets included in rebuild kits, the holes sometimes do not line up perfectly, and this can actually cause the carb to run WORSE than before it was rebuilt.
Another thing to check while it's open is if the power rod slides up and down easily- The power circuit operates by balancing the power of engine vaccum against the power of gravity. If the power rod is sticking, and is not snapping back up when you release the throttle, then that could also choke out the engine with extra gas (this could also contribute to your symptom of it backfiring when you release the throttle at cruise speeds)
L-R:
White 65 Hardtop L60-3-00617 (undergoing restoration)
Red 65 hardtop 4L60-002565 (scrapped for parts)
66 Hardtop "El-Bondo Patrol", L60-00511 (Restored, then sold June2020)
Blue 67 Hardtop (sold March1997)
Green 62 Softtop L60-2-00504 (undergoing restoration)
Hi there guy,are these carby Still any good to run on a Patrol ? I am Looking to buy or Swap for one to run on my 1966 G60.
The fuel does look to low in the Picture, is your pump Supplying the Suffiect fuel to keep the Level ? Also are you running Clean Fuel or The Proper Octane Petrol ?
Maybee it might need a bit of a Tune up, like you said its been rebuilt fairly recently so it should need an overhaul.
This is awesome info guys. I will break down the carb a bit and check the float. I do have an electric fuel pump which is rated 4-7 but it may need some cleaning or a new one. I have a couple mech fuel pumps to go over, maybe one is good and I will switch. I always like the idea of running off the mechanical and having the electric installed as a back up.
The engine and pump were cold/not on when I took the shots so.......maybe okay but that electric set up has always bugged me.
We should start anothe post on the oilbath filter. At what point does it run best? I have one that is all blocked whith crap and one that is pretty clean and they both work the same??? How about a dry filter with an adapter so it could still live in the housing.?
bosque wrote: I always like the idea of running off the mechanical and having the electric installed as a back up.
Me too- My old Chevy Blazer ran a mechanical pump, and I also had a Carter 4-7 lb electric plumbed in behind it and wired up on a switch and relay. This set up saved my bacon twice- once on a 4 wheeling trip, and another on a road trip back from New Mexico when my fuel pump failed out in the middle of the Navajo reservation at 11:30 at night...
L-R:
White 65 Hardtop L60-3-00617 (undergoing restoration)
Red 65 hardtop 4L60-002565 (scrapped for parts)
66 Hardtop "El-Bondo Patrol", L60-00511 (Restored, then sold June2020)
Blue 67 Hardtop (sold March1997)
Green 62 Softtop L60-2-00504 (undergoing restoration)
Not really a conclusion because I still get a sputter when at cruise speed and let off the gas but, oh man, is it better. Idle is low, stays idling when I come to an abrupt halt, sounds happier, I'm happier! I maybe the only one running this carb and did not find one book or article on them beside the Patrol P engine service manuel. The parts book seems to be incorrect on a few parts like it only shows one of the two adj screws and the air bleeder screws need some explanation. If anyone has any literature on the Hitachi VC-42 I'd appreciate the link.
