Prestolite to Thunder Bolt

[two bad]

Got a 1990 volvo penta 570A with a possible ignition issue. Every time i try to throttle up and get into secondaries it wants to backfire through carb and bog out. I believe my distributor advance is not coming in incorrectly thats were the problem begins they do not make replacement springs for prestolite distributor any more or so i cant find them. p.s. i tried the spring kits from parts store not strong enough spring. so i was going to replace the whole system with a electronic thunder bolt system anyone done it what problems occurred any other suggestions thinking thunder bolt because there much less costly the mallory or msd.

 

[wrench 3]

It's more likely that you have a fuel problem.

 

[Bondo]

It's more likely that you have a fuel problem.

Ayuh,..... Agreed,.....

 

[Scott Danforth]

welcome aboard.

while the original prestolite distributor is expensive to repair, you can test the advance with a timing light.

however the lean sneeze that you are experiencing is most likely a fuel problem as indicated above.

 

[two bad]

Been through the whole fuel system not saying I didn't miss any thing drained 120 gals of fuel rebuilt carb new filters tune up no improvements keep coming back to ignition

 

[jerryjerry05]

If you've done the fuel system(tank vent too)
Then check the coil.
See how hot it gets when the ignition is on for a few minutes.
It will get hot but not so hot you can't leave your fingers on it.
If that's ok.
Then probably in the fuel system?

 

[two bad]

Used a known good coil to try same results would love to find replacement springs for distributor but no one can seem to get the correct ones if its in fuel system what's left was thinking about getting new metering blocks but they are clean maybe I donno been through carb a lot tired of pulling it apart

 

[Scott Danforth]

do not assume the advance doesnt work. your VP has a timing tape on the harmonic dampener. in neutral, and in water, run the motor up to 3000 RPM and look at the timing. you should be at 30 degrees BTDC at 30000 RPM with a base timing of 8 degrees BTDC.

you stated you cleaned, the carb, however the Holley on there is very susceptible to dirt. you have to run a fine wire or fish line thru every port and passage. cleaning a carb is not simply a dip and blow off event. Also, which power valve is in the primary side. it should be a #35 anything larger and you will get a lean sneeze (FYI - the powervalve in most kits is not the correct one). which primary and secondary jets?

 

[two bad]

I put the same exact power valve that was in it twice because of all the back firing I can see timing does come up with the light but I am not sure it is coming up at the right time if its too soon is what I think might be happening could be wrong has happened before ran shop air through all the wholes in metering blocks separated from base plate and cleaned. Not sure what size jets are in this carb took them out and they are still clean didn't look at numbers they are the original to the boat and motor

 

[two bad]

O yea i forgot to mention i hate carbs dont know any one made it without fuel injection

 

[wrench 3]

If all else fails check that all the valves have full movement. That's the same symptoms as worn cam lobes. It's not a common problem with Volvo Penta, but the cam may not be original.