New Muffler, new problems

[BKsCC]

I went and replaced the rotted-out muffler on my 149 because it sounded like a chainsaw when it was running (neighbor's words, not mine). I replaced it with the last "Noise Suppression Muffler" kit CC Specialties had in stock just before thanksgiving when the temps were in the 50s.

https://www.ccspecialties.org/pics/I...LER%20KIT2.jpg

Tested it and it fired up a little harder than it did before, but once it got running it was fine, and indeed much quieter.

Today it snowed for the first time, was 30 degrees out, and it refused to start up all day. I have a 400 CCA battery on it, it's been on the charger all night, and I even had my block heater running on it for an hour. Ether wouldn't do anything to start it either, but that's because I suspect I flooded it prior to trying that.

Once it's done evaporating the fuel out of the spark plug hole, what do I need to set up differently with the new muffler? I'm guessing it's got more back-pressure than it was used to? I can't think of anything else to try other than adjusting the carb.

On the old shot out muffler it fired right up with 30W oil all winter long last season, down to 10 degrees. I wanted to get some 5W-30 in it for this winter, but didn't because I was waiting for a warm engine to drain it properly; was planning on doing it when I shut it off this morning but obviously here I am asking for advice.

TL;DR: New, bigger muffler meant for a 149 changed the back pressure so now it won't start anymore. What can I do to correct for it shy of changing mufflers again?

Thanks all!

[Billy-O]

First off, I think if back pressure is going to affect the engine it would do so with the engine running. Not starting up. I may be wrong, but I suspect something else is the cause of your problem.

Secondly, I'm having difficulty interpreting your problem. Is the engine turning over too slowly starting from cold as if weak battery or is it turning over acceptable but not starting easily?

[athomas]

Originally Posted by Billy-O

First off, I think if back pressure is going to affect the engine it would do so with the engine running. Not starting up. I may be wrong, but I suspect something else is the cause of your problem.

Secondly, I'm having difficulty interpreting your problem. Is the engine turning over too slowly starting from cold as if weak battery or is it turning over acceptable but not starting easily?

Agree sounds like some other problem reared its ugly head ! I'd check the timing,points.plug,plug wire,fuel supply and even the choke cable clip, I've found them missing and when you think your giving it some choke it's only moving the cable in the housing instead of moving the choke, I just don't think the new muffler would cause you a big issue as far as starting unless it was completely blocked !

[BKsCC]

Starter turns over strong, can go for a full 30seconds without losing power. If it's a starter issue it'd come as a surprise because it put-puts along nicely with the battery its on.

Issue showed up immediately following the muffler change. We even did a before and after and noted how it suddenly got really sluggish on start up.

I replaced the spark plug, wire, battery last year when I got it. The battery's been on a battery conditioner/charger for a week in anticipation of the snow.

It used to fire right up after cranking for only a few turns.

I also thought maybe my choke cable decided to get weird on me, because I've just replace the throttle cable connection nut at the governor linkages. All is as it should be there.

So unless my timing suddenly threw itself off suddenly between mounting my snowblower on Thanksgiving and today I'm at a loss.

Perhaps the new back pressure messed with the valve timing? If they were sloppy before and I didn't notice maybe this exacerbated something?

[darkminion_17]

put the old one back on and see if it makes a difference.

[BKsCC]

The old one kinda disintegrated when I took it off, there's nothing left to mount it with.

I could run it straight-pipe, but that kinda defeats the purpose, and if it works straight-pipe then I'm still faced with the same muffler induced problem to solve.

[Hairtrigger]

Originally Posted by BKsCC

The old one kinda disintegrated when I took it off, there's nothing left to mount it with.

I could run it straight-pipe, but that kinda defeats the purpose, and if it works straight-pipe then I'm still faced with the same muffler induced problem to solve.

Try it with no muffler then

[RustyShackleford]

If it won’t even cough to life on the funny gas, I would suspect an ignition issue before an exhaust issue.

[BKsCC]

Update:

Won't fire at all. Ignition seems to be working, I'm getting a spark. It's also 20 degrees warmer today so it's not the cold. This is with the muffler on and off. Floods real good though. Must be a carb setting issue, man I hate fiddling with it because I never get it right and it haven't touched it in a year since I managed to get it working.

[Billy-O]

Check the timing first before laying the blame on a carb issue problem. You write of flooded issues but I would expect to see carburetor leaking fuel on the ground, too!
If the timing got knocked out of whack, you may still have spark. So therefore, if timing is out and you are trying to start engine, the fuel would be drawn into cylinder making you think the motor is flooding but it does not fire because the timing is out.

Also, confirm you are not trying to start tractor with snow thrower engaged.