korthos

87 civic hatch 1.5L carb. car started loosing power after driving above 50mph for about 2min. it has 320,000 miles and the head gasket has been bad for about 25,000 miles. I just figured the head gasket was getting worse and noticed that there was some coolant getting into the oil so I put in the spare motor I had with only 176,000 miles. I put the carb on the doner motor because the other motor had been sitting for a few years.

car drove fine for a few days with newer motor installed then started flooding real bad after driving for 15min. Installed new float valve and seat. car drove fine for another few days and now its back to loosing power while cruising. if im on level ground I can seem to stay at a steedy speed but if I go up hill at all it stumbles and looses speed. if I push in the clutch and coast for 30sec or more it will drive ok for about a min then start acting up again.

im wondering if the fuel pump is pumping to much or not enough at cruising speed, or if perhaps too much pressure is building up in the fuel tank. I took the gas cap off when I got home and there seems to be a lot of pressure coming out. any help will be greatly appreciated, thank you

ezone

Fuel filter.
Or a fuel delivery problem....
Fuel filter first. Cheap and easy.



#2 (ramdom car pick) Available at most parts stores.

korthos

I replaced the fuel filter when I put the motor in

Gunner

is the spare motor the same one? If filter is good it could be the pump..idk

korthos

spare motor is the same. same year hatch same color everything.

ezone

Still sounds like its running out of fuel. Classic symptom description. Fuel delivery problem.

WHICH filter? The one pictured in my last reply, or the one in the engine compartment? (I just found this today, it is not labeled in the Majestic site at all.) (Also, my dealer catalog says "not available" so you would have to improvise with another inline fuel filter.)

Item #1 in this pic is called "fuel filter B"





What about the REST of the fuel system?

Tests can be done to a mechanical fuel pump, vacuum and pressure.

Fuel pickup tube strainer (sock) inside the gas tank clogged?



Although PRESSURE in the fuel tank absolutely cannot cause your symptom, a vacuum in the tank can cause the symptom.
If you think the venting of the gas tank is the issue, test that by removing the fuel cap and then do your 2 minute uphill test drive. I'm sure that is not the problem though, but the test above is quick and free.

korthos

I changed the filter by the tank. checked fuel pressure at the pump and its only 1psi. Not the 2.7-3.8 that its supposed to be. pressure doesn't change with rpm's at all. Pump is only $14 and it will be in tomorrow morning.

korthos

Installed new fuel pump, same problem. drove the car till it started acting up then shut it off right away and pulled over to look at the fuel lever in the carb and it was right where its supposed to be. So it seems that its not a fuel problem.

korthos

disconnected the lower vacuum hose on the dist and plugged it. drove the car and it didn't stumble at all but it did not want to gain speed over 60mph after a few min

ezone

FYI: Just because you saw the fuel in the little carb window once you got stopped, does not necessarily mean that it wasn't low while under a load.

Ideally, you really need to be able to watch it while it is running poorly.

The pump could have refilled the carb bowl as soon as you removed the load from the engine, during the time it took the crankshaft to coast to a stop. The moment you took your foot off the gas pedal, that bowl started refilling. So by the time you got pulled over and the hood up, it looks full.

I still think you are using fuel faster than it can be pumped.
Do a fuel pump volume test. (I can't tell you Hondas actual specs, just a general figure that should work for all applications.)
Take the fuel hose off of the carb bowl inlet, run the end to a jug. Have someone start the engine, rev it up to about 2000 RPM and hold it there. Will the pump deliver approx a pint of fuel in 15 seconds? How about 30 seconds?

korthos

Fuel flow tested fine.

korthos

Replaced the carb isolator because it was cracked and leaking, still didn't fix it. Pulled the carb, isolator, and everything vacuum related off. Made an adaptor and installed an old carb i had off of a 71 super beetle. Drilled out the jets a bit and it runs great

ezone

Old thread is old, I know. Found this notification in old email.

Interesting fix, to say the least!

...So the problem must have been within the carb itself. You said you replaced the float needle and seat, I wonder if the "float drop" adjustment was in spec? Or maybe the inlet fitting was restricted somehow.