engine and drivetrain Loss of power to engine in 76 polaris

[Feefela]

HI guys!

 

So my sweet 76 Polaris is still having trouble. A little history: I got her switched from an automatic to a 4 speed a month ago, and after the conversion she was running really rough- wouldn't go over 40 on the freeway and there was this constant pull-back jump/chug thing at higher speeds. A friend and I (the friend being a professional mechanic) swapped out the carburetor and reset the timing, she drove better (though the problem was still there) for a while, then yesterday, on the freeway, it felt like no more gas was getting to the engine and within minutes she lost power. I had her towed home.

 

I plan on swapping out the points Sunday. Do you guys think that would solve the problem or is there anything else I should go ahead and do at the same time? I'm gathering parts tomorrow to have a friend help me get her running Sunday. So far I plan on picking up a feeler gage and new points.  Any other ideas?

 

A little more history if it helps: she was sitting outside for around 4 years (from 04-08 maybe) near Seattle Washington. I have been driving her off and on since then, but she has never run great. I thought the smog stuff still latched to the engine was the problem, but that has recently been removed and the problem, while better, still persists.

 

Thanks for anything you can think of!

Best,

Fiona

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[repoman]

Back in the day, when I had a 76, the idle jet on the stock solex carb would get clogged and the car would not run....what carb to you have?

 

I am assuming you drained the gas, since it was sitting so long....

 

Did you happen to cap off all the vacuum lines on the intake manifold?

 

Also, are you planning on keeping the car registered in WA?  If not, you might have just taken off the smog equipment for not, as you will need these for CA.

 

Just some thoughts

Edited January 29, 2016 by repoman

[percy]

 

A little more history if it helps: she was sitting outside for around 4 years (from 04-08 maybe) near Seattle Washington. I have been driving her off and on since then, but she has never run great. I thought the smog stuff still latched to the engine was the problem, but that has recently been removed and the problem, while better, still persists.

 

 

 

Based upon your underscored comment, I doubt ignition points is your problem, although setting them to .016" is never a bad idea. 

 

You really need to establish a base line of information about that engine.  In particular, it would be helpful to know the compression readings.  If you have low and uneven compression, all of the ignition timing and carb settings will be in vain.  If you have acceptable compression, even if on the low side, which one might expect from a worn 1976 M10 engine, then a major tuneup is in order.  That includes checking the valve lash, adjusting the timing, points, plugs and insuring that you have a fuel system that is clean and functioning properly.  All of these systems need to work in concert with one another for a decent running engine.

Edited January 29, 2016 by percy

[achman]

I'm guessing rusty gas tank and clogged fuel filters. From personal experience, I would drain tank, have cleaned, replace all fuel lines and filters, then see how it runs...this is not electrical I don't believe.

[Hans]

I'd be looking in the fuel tank, and at the pick-up filter, then the lines, fuel filter. If it sat for 4 years with ethanol based fuel, I suspect you've got a load of gloop in there.