PDA

View Full Version : Engine problems


Voodoo
06-02-2012, 04:25 PM
Folks --

87 Prostar -- 351 Indmar.

First engine start attempt of season was last week. No go. Battery was on charger for 24 hours beforehand but still weak. Battery was 6-7 years old. Points were looking corroded.
Engine would not fire.

Today I replaced the battery and the points, cap, rotor and condenser. The engine fired in less than one second but would not remain running for more than 3 seconds. Suspecting a fuel delivery issue I cleaned out the fuel filter sump, which was full of crap, and cleaned the filter screen at the carb fuel line attach point. Once all was reassembled I verified strong fuel delivery at the carb but the engine would not run for more than 2-3 seconds.

Then another problem. The starter began to "tick" (not engage) every other attempt, then every attempt. I removed, cleaned, and reattached all leads to the starter and the starter relay but still the same.

So, here is some amplifying info --

starter and starter relay are 12+ years old
carb rebuilt 7 years ago
alibis: I did not time engine (can't find light), set point gap only

I think the starter is shot
Any thoughts as to why the motor runs for 3 seconds then quits?

Voodoo

mig
06-02-2012, 05:07 PM
Voodoo, some starting points. Clean every ground you can find - grounding problems can happen over the winter. Check the ignition switch posts - I have had switches go bad during winter storage. I also remember condensers giving short run times when they went south, you might try the old one again if you can't come up with anything else. Also if you messed with the starter/solenoid; is the ignition feed wire from the solenoid on the keyed (starter) post? That would shut power to your points off when you let off the starter. If you could verify that you still have spark when the engine quits it could help diagnose a sticky float/needle in the carb. Good luck and good skiing!

Folks --

87 Prostar -- 351 Indmar.

First engine start attempt of season was last week. No go. Battery was on charger for 24 hours beforehand but still weak. Battery was 6-7 years old. Points were looking corroded.
Engine would not fire.

Today I replaced the battery and the points, cap, rotor and condenser. The engine fired in less than one second but would not remain running for more than 3 seconds. Suspecting a fuel delivery issue I cleaned out the fuel filter sump, which was full of crap, and cleaned the filter screen at the carb fuel line attach point. Once all was reassembled I verified strong fuel delivery at the carb but the engine would not run for more than 2-3 seconds.

Then another problem. The starter began to "tick" (not engage) every other attempt, then every attempt. I removed, cleaned, and reattached all leads to the starter and the starter relay but still the same.

So, here is some amplifying info --

starter and starter relay are 12+ years old
carb rebuilt 7 years ago
alibis: I did not time engine (can't find light), set point gap only

I think the starter is shot
Any thoughts as to why the motor runs for 3 seconds then quits?

Voodoo

Philscbx
06-03-2012, 08:32 PM
The slow speed circuits is more than likely plugged - in the carb.
You can tell moving idle screws and no response.

If carb has choke plate - move it near closed by hand as it starts - and modify as needed to keep running.
If you can keep it going this way - give it short full closed choke - to pulse in a rich load of fuel.
Then open as needed to clear it to idle - a few cycles of this might get idle circuits wetted enough to clear up.

Remove Idle/air screws - jet some cleaner directly into ports they came from.
Make sure spring/o-rings don't escape for these screws.

If it's still stubborn, squirt carb cleaner directly into carb vent,, and restart.
It might take a few minutes -
You might get lucky- or it will say - I need deeper help - need to get inside and power clean it with cleaner/compressed air.

On the starter - pull it apart - inspect brushes & armature - Clean out copper debris grindings and lube bushings - assemble - load brushes back in holders with springs cocked to the side to hold brushes away from armature.
Once armature is in place - release brushes.

If bushings are sloppy on the shaft, armature will try to skid into field-windings - inspect for any signs on the armature.
Bushing /brush kits are avail if you want to save a few rounds of happy hour.

The starter relay also may need to be replaced - it needs a solid hit internally with roughly 500-600 amps when under load rolling the engine over.

If no timing light available - gap the points with matchbook cover & if distributor wasn't moved, timing will be just about dead on with points setting.
Make sure to coat rubbing block with a good teflon grease.

Fog the entire assembly with a LPS product - and make sure advance plate weights under rotor are free to move & lube pivots.
Grab plate for rotor, with rotor off, and twist it back & forth to verify weights move in & out.
WD-40 is strictly a solvent - use it only to scrub rusty surfaces off.

Hope it works out -

Voodoo
06-05-2012, 10:45 PM
Folks --

Thank you for your replies. You gave me a good vector. I've ordered a few more parts and will get going on your suggestions. Thanks again.

Voodoo