Why would Boxxer enigne cut out at full throttle???

[Guest]

I have a well used Boxxer (2100 hours) with the Briggs engine. Normally its my backup but I"ve been using it the last week or so. When its at full throttle it sounds like its cutting out a little and every once in a while I hear it backfire.

It doesn't cut out to the point where I lose power but I'm afraid if it gets worse I'll be in trouble.

Any ideas?

 

[Blue Monarch]

Air filter getting clogged? When you blow foam through the blower, all hell breaks loose because of back pressure. It has happened to me a couple of times. I can only imagine what kind of crap went through my engine.

 

[Becker]

OK, engines are pumps, they suck air in and pump it out. I hope when you get water in your blower it is not getting in your engine.

My thoughts.

I agree with Dirk on the air filter.

Spark plugs.

But more likely I'm thinking you might have a sticking valve.

 

[Blue Monarch]

That's what I thought too Becker. Air filter would clog nearly instantly when the blower thing happened. How could that happen if the crap didn't go through the engine. Not saying you're wrong, I just may not get it.

The filter was so fouled that the engine would die. You could run a filter for years under regular condition without that happening.

 

[Becker]

That is insane!

Just does not seem logical. But anything is possible.

Speaking of Air filters, I'm not sure I've taken a peek at mine in awhile.

 

[Becker]

would a exhaust valve not closing all the way allow foam to be sucked from the heat exchanger?

HMMM...

 

[MerCrewser]

Sounds like it is running lean. Try a half turn out on the high speed mixture screw on the carb.

 

[RichardnTn]

A dirty air filter at high rpms tend to bog the engine down continually, not intermittently. Sounds like carbon build up on an exhaust valve not allowing a good seat....or could be a week valve spring....probably time for a valve job... Hope ya get it fixed...Richard R

 

[joey895]

My first thought is bad gas or water in the gas especially if it sits for any period of time you can get condensation build up in the tank. I just had a similar problem. The first things I would would take care of bad gas and just so happen to be the cheapest and easiest as well. I would change the spark plugs and fuel filter, pour a container of heet (water remover for gas) into your gas and top off your gas tank with fresh fuel. This is what I did and it solved my problem quickly and cheaply. I also now carry extra plugs and a fuel filter on my truck. 8)

 

[Becker]

AZ does not know what condensation is.

 

[Jeremy]

Out of gas?

 

[joey895]

AZ does not know what condensation is.

Good point I didn't pay attention to where he was located. Here every breath you take is like taking a big swig of water. :shock:

 

[Jimmy L]

Spray some carb cleaner down the carb as its running.


Make sure and work the throttle to keep it fron stalling.


Bad gas will do it too.

 

[Jimbo]

Curt...I'd include checking all the electrical connections that go to the engine...it seems like some of them can easily come loose with time and vibration...make sure they are all plugged in firmly!- Jim

 

[Jim Williams]

I would start by replacing the sparkplugs. Even if they look O.K. My Kohler bogs down if I get too many hours on the plugs.

Why are those 2 words in yellow?

 

[R W]

Could it possibly be a clogged fuel filter?? Fuel starvation?? I'd start there.....

 

[Becker]

RTS sold his.. and for all I know it could have been to Curt.

Oh wait. RTS said he would not sell it to him even if he wanted to buy it.. never mind

 

[Guest]

WHAT'S BROKEN ON YOUR BLUELINE THAT IS MAKING YOU ARE RUN THE BOXXER???

 

[Becker]

My guess is the Blue like is like a wife.. Sometimes you just want to play with the EX

 

[adamh]

My Boxxer 427 was doing the same thing. The choke was viberating out and choking the engine.

 

[J. R. Nation]

Take a look at spark plug boots , rubber will brake down & let it ground out to shroud ( might see it arc in dark ) .

 

[Duane Oxley]

Sounds like it may be either running out of fuel (i.e., a carb problem, or possibly fuel filter partially clogged...) or it's running "into" back pressure in the exchangers / exhaust plumbing, at higher RPM.

 

[Larry Cobb]

Curt;

It may be ignition breakdown.

The ignition coil is under the most stress at full throttle.

A backfire may occur from a no spark condition.

Larry Cobb

 

[Becker]

Curt will be busy for a month checking and testing all this

 

[The Magician]

Take a compression test. B&S have valve and carbon problems with those hrs. It only takes a few minutes and give the whole picture of the eng. If Ok check the choke closing.


Now you see it...but where?

 

[minuteman]

It can only be one of two things, fuel or spark, check or replace fuel filter and float bowl for crud if it still occures than it is the coil wires breaking down. Brigs coils are at the end of the spark plug wires and it gets its juice from the turning of the main flywheel off the magnets in it . Backfire = timing - spark .

Greg