Nother Merc 470 Stalling Question

[vtboatr]

Edit:
Wrong forum, could a mod please move it for me? :redface:



1st thing though, cool site.
I've founds tons of great info surfing and using the search function.

New to me boat with stalling issues on acceleration.
(81 Sea Ray w/the imfamous 470)

Runs excellent until it's warm/hot-ish.
Seems to act like it's loading up, starts back up and idles but when put in gear stumbles and dies.

*Bad gas? - Could be but I've run over 15 gallons of fresh through it with no change or improvement.
*Changed over to elec. ignition and it runs better overall but problem is still there.
*Cap/rotor/plug wires all like new, timing is correct.
*Anti siphon valve and throttle cable both replaced by the P/O chasing the issue.

Next step will be replacing the plugs and testing.
I'm wondering about the coil now also.

What's next to check off the list?
Accelerator pump?
Fuel filters?

At speed, it runs out sweet...any advise?

 

[Bondo]

Re: Nother Merc 470 Stalling Question

Ayuh,....

It Sounds like a Carb issue to Me.... Probably needs a Cleaning,+ Rebuild....

 

[vtboatr]

Re: Nother Merc 470 Stalling Question

If it was a carb cleaning/rebuild issue, wouldn't it act up all the time?

Doesn't seem like it would change from cold to hot, a poor running carb runs poor all the time...no?

 

[ncs2929]

Re: Nother Merc 470 Stalling Question

I hope it's okay to post other sites if not please let me know. But I have a 470 also and found tons of info about only 470's on "Breezeworks 470 Forum". I use both of these forums and they are fantastic.

Nels

 

[vtboatr]

Re: Nother Merc 470 Stalling Question

I hope it's okay to post other sites if not please let me know. But I have a 470 also and found tons of info about only 470's on "Breezeworks 470 Forum". I use both of these forums and they are fantastic.

Nels

Thanks for the site addy, I'll have to check it out.


Did some more puttering for tomorrow's run.

Changed the plugs, lowered the idle and found that the idle screws weren't even, one was 2+ out while the other was less than 2 turns out.
Turned em in, out 2, then in until the idle dropped some, ended up around 1-1/2 out, maybe a touch more.
Idles better now...

Will be ordering a Flame Thrower coil soon also, to take advantage of the elec. ignition.
Should allow for a bigger gap on the plugs.

 

[vtboatr]

Re: Nother Merc 470 Stalling Question

Post yesterday's run, it's a lot better but not fixed yet.

I did find that the filter over the pump didn't have a spring holding the filter in place, I wonder if that could cause any funny business...?

Checked the coil when it did act up and it was hot but how hot should they be when running?

 

[searay3]

Re: Nother Merc 470 Stalling Question

Changing the coil isn't going to hurt if you have the extra 30 bucks, But I'd have to agree with Bondo. Temp has everything to do with how a carb functions. When cold, mix is regulated by choke. PO's been chasing the problem, what did he do/replace? Just remember another bit of wisdom from Bondo....rebuiding an old carb is 50/50 shot because of deterioration of the carb body. Needs soaked and passages blown clear with compressed air. My 2 cents..

 

[vtboatr]

Re: Nother Merc 470 Stalling Question

Well...
Checked the choke sitting here in the driveway and it turns out I can rule that part out, it's wide open with zero tension from the spring coil even dead cold, meaning it's not yet ever been choked since I've been running it.

Could be in the transition circuit I guess but I'll leave the carb rebuild for last.

The new coil will allow for a larger plug gap, seems like a good idea to take full advantage of the elec. conversion IMO.

 

[vtboatr]

Re: Nother Merc 470 Stalling Question

Ttt

 

[vtboatr]

Re: Nother Merc 470 Stalling Question

Another year in...

Seems to be a case of the coil getting hot.

When it acts up &/or stalls then won't start, the coil is very hot.

When I change out the hot coil for a cool one, it'll start and run good again.

Thing is, why is the coil getting hot?

Could it be ambient temps in the engine cowl doing it?
Bad plug wires? (only thing that hasn't been changed out yet)
Low voltage to the coil?
(getting 11.5v until I hook up the elec. ignition module, then it drops to 7.4v)