mercury 470

[crazyhorse83]

my port engine, the famous 470, has got a ghost in it. it will start, run great for a few minutes. and then out of nowhere it will just sputter out! I believe I've been through everything with this engine trying to fix this problem. taken the carb apart numerous times checking float levels/leaks and whatever. checked the timing and firing order, it is correct. compression it ~125 on all 4. idle mixture screws 1 1/4 turns out. has spark of course. checked the points and I believe they are good enough. I have changed the fuel pump with a known working one. two different fuel supply's (the boats tanks and a portable) the timing is close enough to run and I can change it very easy. have oiled the advance weights in the distributor, brand new plugs. today I am going to try bypassing the engines power to the coil. could a bad regulator cause a reduction in power to the coil after warming up? I'm running out of ideas...

 

[JustJason]

Re: mercury 470

Welcome to Iboats...

You need compression, fuel, and timed spark to make an engine rune... so which one are you loosing?
When it stalls does it fire right back up, or does it need to sit a bit before it will run again?

the timing is close enough to run and I can change it very easy

Eagh... timing should be spot on, as timing and dwell effect eachother. Did you verify your dwell with a good dwell meter?

 

[Bondo]

Re: mercury 470

and then out of nowhere it will just sputter out!

Ayuh,... Right Exactly at That Time,... Do your Diagnosis...
It's lacking Fuel, Fire, Compression, or Timing...
Compression,+ Timing don't change, so Diagnose whether it's loosing it's Fuel, or Fire....

Mornin' Jason,... I guess your multiple digits are faster than my single digit this mornin'....

 

[JustJason]

Re: mercury 470

Mornin to you to Bill, hope is well up north...

I've never had a problem with the fingers... it's my dang skiiers knees that kill me every now and then

 

[crazyhorse83]

Re: mercury 470

I think it was flooding out the engine, it was pouring gas from the venturi arms after stalling, I believe I've fixed the problem by re-setting the float level (it was to high). can I check the dwell when its not running? points are set at .20

 

[JustJason]

Re: mercury 470

I believe I've fixed the problem by re-setting the float level (it was to high). can I check the dwell when its not running? points are set at .20

1rst... if it's dumping gas down the venturi then it is flooding out. Causes of that can be wrong float height, bad fuel pump, dirty carb, or bad carb (carb's do go bad and need to be replaced, not just rebuilt, happens more than you think). So now you need to figure out which one it is.

2nd, on to your points. Point gap means nothing, all it is, is eyeballing the dwell before you can get a meter on it. Setting gap gets it close enough to run, but the dwell needs to be dialed in to run correctly at all speeds. Dwell really needs to be checked running. It can be checked cranking, but that's awefully hard on the starter motor and battery. Besides, cranking rpms will be to low to accurately measure it anyways. Gap should get it close enough to run, then put a meter on it.

 

[crazyhorse83]

Re: mercury 470

we finally got it to run today. it wasnt fuel, compression, or timing. turns out it had no spark... it was assumed spark wasnt a big issue cuz it started up and ran great for a few minutes, up untill it died. anyhow coil tested fine with resistance, but produced no spark on the coil testing machine. ran without spark, interesting

 

[rodbolt]

Re: mercury 470

try running a seperate ground wire from the point contact plate to a known good ground.
it happens.
ran me up the wall once.