No Power under load

[mookiex4]

Hi all,

I have a 1965 GMC with the 305 V6. It has started acting up, by losing power under load. When climbing a hill I have to shift down just to keep it at 40 if I am lucky. Starting from a stop it really drags.

I gave it a full tune up with new points and nothing.

I timed the engine and nothing.

The carb is less than 2 years old and adjusting the fuel mixture hasn't helped.

I converted to an electric fuel pump. Didn't help

The engine has a rebuild less than 50k. I am at a total loss. I am trying to keep it running long enough to get my 327 from my fathers place which is unfortunately out of town.

Any help or suggestions would be greatly appreciated.

Mark

[1963c-10]

Whats your fuel pressure? Sounds to me like a fuel pressure issue if runs fine except under load or going uphill.

[mookiex4]

Thanks for the reply. I was doing some reading and found that when i set the timing at 5 degrees off of TDC, it is actually around 2.5 or 2.7. When I timed it I also did not disconnect the vacuum advance line so it may be way off. If timing it correctly does not fix the issue I will check fuel pressure.

Thanks,
Mark

[1963c-10]

Sounds like a plan.

[63burban]

Catalytic converter is plugged ! B>}

[luvbowties]

Originally Posted by mookiex4

Hi all,

I have a 1965 GMC with the 305 V6. It has started acting up, by losing power under load. When climbing a hill I have to shift down just to keep it at 40 if I am lucky. Starting from a stop it really drags.

I gave it a full tune up with new points and nothing.

I timed the engine and nothing.

The carb is less than 2 years old and adjusting the fuel mixture hasn't helped.

I converted to an electric fuel pump. Didn't help

The engine has a rebuild less than 50k. I am at a total loss. I am trying to keep it running long enough to get my 327 from my fathers place which is unfortunately out of town.

Any help or suggestions would be greatly appreciated.

Mark

1-Distributor slipped and turned on you? Reset timing & check for normal power. 2-Check for timing chain having jumped: As you temporarily advance timing, if eng speeds up as you do so (even if it goes several degrees above spec) and it gives more power, likely the t-chain has jumped. If you determine this is the problem, I wouldn't drive it far/fast until problem is corrected.

[awbrown]

What carb is on it?? I would check to make sure that the centrifical advance didnt freeze up . you can check it with your timing light by disconnecting the vacum advance and rev it up while watching the marks it should advance as engine speed increases.... also the power valve can get stuck causing a lean mid throttle , used to happen with Qjets all the time....