Hey all, I'm having some issues with my engine. its a 1.7L Dual Carbed. Everything electrical is brand new, Plugs, wires, distributor, (including points), coil. I believe its getting proper gas flow but it's weird though because it idles fine. If reved and the instantly released it sounds great kicks right up no problem, however if brought up to about 3500-4000 or greater and held, it makes a poping noise and looses rpms. also on take off, give it a couple revs, sounds great, put it in first and take off, it'll throw you back in the seat then it hits about 3000 rpm and starts bogging down, shift to second and its about the same deal. In 3rd it starts to bog down and tops out about 45mph. 4th is really starting to bog and on the road can hit about 50. 5th gear is a notch above chugging it out completely. pedal clear to the floor and its loosing speed, any ideas guys?

1 Bad gas
2 Carbs
3 Fuel pump

...I had a similar issue with my Pontiac tri-power many years back, the carbs were picky about gas and gave me hell after each rebuild...


Hah! And I thought dividing an 8 cylinder in half would be easier

Forgot to mention, Carb kit is brand new, along with new low pressure pump, and a cleaned gas tank. Not ruling this out as a problem, just think its still unlikely

I am thinking carb sync/ cross link bar adjustment. I would check the cross link bar to make sure the carbs are getting the same amount of gas at the same time.

Thats a good idea, hadn't considered that yet

What kind of air cleaners are you running? What kind of carbs?

I had problems like this with water in the jets in my webers. I removed and cleaned the jets and the problem went away. It is an easy check.

Valves/valve adjustment. Too tight will cause this.

all great suggestions guys, but i think we resolved that the problem runs deeper. Getting low compression (30) in #3 and about (60) in #4, didn't even bother checking the other 2, engines gonna have to come back down, new seal kit, Took a shortcut and payed for it in the end.

I had a similar problem. I ended up being the fuel filter. As fuel velosity increased a large burr from machining would clog the output barb. The engine would die when it reached 3500rpm.

If your compression is that low, you have other issues...

Check your valve adjustment first.

Agreed w/valve adjustment 1st - easy speasy compared to a reseal 1st.

I had a very similar problem. Resetting my points gap and timing resolved it completely