Boxxer engine woes.....

[Blue Monarch]

So, my boxxer has a 21HP Briggs Vanguard engine. Here's the deal....

Engine was spraying a fine mist of oil all over the place so I took it in. Turns out the rear seal was bad. Had small engine shop fix it.

When I got it back, the damn thing would barely run when under load until it really warmed up. Even then, it had to be run with the choke pulled out somewhat. Was backfiring on shutdown about half the time. Also noticed fuel is getting into the oil also. .

I don't know squat about repairing a rear main seal on a small engine. Could something during that repair have caused this? None of this was happening until I got the machine back.

On the plus side, it no longer spews oil!

 

[Charlie Lyman]

It sounds like the motor could be shot.

 

[Shawn Abbey]

1. Is may be possible that the repair technician may have reassembled the engine without matching the timing?. Some of your symptoms point to a possible timing issue.

2. Fuel in your oil shows fuel is leaking into the combustion chamber, past the piston rings, and into the crankcase while the engine is not in use (overnight). Usually, this is caused by a stuck needle valve in the float bowl of the carburetor, causing fuel to continually flow. A simple cleaning of the needle valve in your float bowl will likely be the repair that's needed. After this repair, you need to check and/or replace your fuel filter, and perhaps install a fuel shutoff valve to prevent this in the future, should the needle valve fail again.

 

[Becker]

I'd guess timing. And perhaps he reconnected the choke wrong.

 

[John Olson]

Time to upgrade. Drive it to utah and ill give you our push pull or drag in trade in of $2500 and or more on select machines only.

 

[Becker]

How many hrs do you have on that 421 now?

 

[Blue Monarch]

not enough hours Beck!

Gonna do a carb rebuild. If that doesn't work, I'll have em check out the timing.

 

[Becker]

What does the small engine shop say?

 

[Blue Monarch]

They say try the rebuild kit. They never mentioned timing.

 

[Jimmy L]

I have an old lawn mower with a Briggs 5 HP engine that you can have if it will fit.

 

[Clean Response]

Take to the shop and have them fix it.

Just like if you cleaned a carpet and a spot came back you would have to fix. They need to fix it. You took it to them with a seal problem now there is another problem, why did they not see/spot it when working on it?

 

[Blue Monarch]

Sorry, I was a bit unclear. I'm not doing any of this work. Shop always does it.

 

[dealtimeman]

Yes, you are on the right track, I think you have a Nikki' carburator. Have them completely tear it down and leave in a carb cleaner solution or better yet have them put in in a carb cleaner in an ulstrasonic cleaner over night. Replace all gaskets and check intake screen. Replace fuel float and seal and pin. Jet all fuel routes and passages by hand with carb cleaner to insure all passages are clean and clear.

I just replaced a boxer 421 motor and the owner quite liked the upgrade as the 21 hp b&s engine is no longer available and replaced it with a 23 hp b&s for 1750 and the new engine does not miss a beat and is very strong. It takes slight modification and some patience but engine fits with a little tweaking.

If you need the carb off the old engine that I just replaced ( engine had no compression on one cylinder, carb is fine) let me know.

 

[Becker]

I only asked about Hrs.. Cuz I wonder.... Time to drop in a new engine?

 

[Blue Monarch]

I was wondering what engine I would replace it with. If it comes to that.....I hope the tweaking isn't an issue. Worries me because of the coupler. I would think a belt driven blower would be much more forgiving.

Sent from my SPH-L720 using Tapatalk

 

[rwcarpet]

So, my boxxer has a 21HP Briggs Vanguard engine. Here's the deal....

Engine was spraying a fine mist of oil all over the place so I took it in. Turns out the rear seal was bad. Had small engine shop fix it.

When I got it back, the damn thing would barely run when under load until it really warmed up. Even then, it had to be run with the choke pulled out somewhat. Was backfiring on shutdown about half the time. Also noticed fuel is getting into the oil also. .

I don't know squat about repairing a rear main seal on a small engine. Could something during that repair have caused this? None of this was happening until I got the machine back.

On the plus side, it no longer spews oil!

Just a thought.....did you check for any vacuum leaks? Any intake gasket leaks? You're describing the same symtems I had with the Genesis Ford engine 2 weeks ago. Mine would only run if the choke was fully out. Found an unplugged hole in the intake manifold. It was sucking air. Plugged it up and good as new. As for the gas in the oil, if you're running with the choke set, you are dumping lots of fuel into the manifold. Just start it up and check for intake vac leaks, before you do any other repairs.

 

[dealtimeman]

If you decide to change out the motor I have the direct replacement motor model type in. My office just let me know.

 

[Blue Monarch]

Much appreciated. Hopefully, I wont have to go that route!

 

[Becker]

Much appreciated. Hopefully, I wont have to go that route!

When you do, you'll be rocked.

over the years you may not notice the decreased power of a engine, or remember the fast starting, or smooth running.

If all else on the machine is good a new engine will almost like a new TM..

 

[Mike Cecil]

I was wondering what you have to do to the boxxer to make the 23 hp motor fit?