# Briggs Intek Twin running issues



## Country Boy (Mar 18, 2010)

I have a Briggs & Stratton Intek model 407777-0138 E2 that is having some weird issues. I had to repair the governor on the unit because the governor gear had seized to the shaft and spun the shaft in the block. The customer didn't want to install a shortblock (pin not available separately), so I had a local machinist make a new shaft with an oversized bottom to fit the enlarged bore and I installed a new governor assembly. I reassembled the unit, but when I ran it, it was running rich and popping out the muffler. I checked the carb and found it clean, however the needle was badly worn, so I disassembled, cleaned, and rebuilt the carb. While reassembling the manifold to the carb, I noticed that the manifold was slightly warped where it bolted to the carb and wasn't sealing properly. The customer didn't want to spend the money on a new manifold, so I sealed the gap (only a couple thousandths) with Ultra Copper sealant. I figured that had to take care of it, so I got it back together just now and ran it, but it still runs the same. :argh:

I tried pulling a spark plug wire on each cylinder in turn to see if one side or the other was causing the problem. That's when I discovered that removing one wire causes the running issue to go away completely. It runs smoothly on either cylinder, but when you put the second spark plug wire back on, it immediately starts running rich and popping out the muffler. The exhaust also starts to glow after a few minutes, and your eyes start watering from the extreme amount of fumes the engine is giving off. Pull off one of the wires and it will run smoothly and the fumes go away. 

So, anyone have any ideas? What gets me is that it will run on either cylinder smoothly and evenly, but when you try to hook up the second one, it will just spit and sputter. The spark from both coils is great, a nice hot blue/white spark and it appears to be even with no missing. Help me out here before I pull what's left of my hair out! :dazed:


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## txsteve (Dec 4, 2011)

Valves not seating


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## Country Boy (Mar 18, 2010)

I had thought of that, but that doesn't explain why it runs fine on each cylinder separately, but runs like crap when both plugs are hooked up. I'll have to do a leakdown test on it today and see what I find.


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## Country Boy (Mar 18, 2010)

Leakdown test showed 85% leak in both cylinders. I'll have to talk to the customer before I open anything up because he didn't want to spend a ton of money on this thing. It seems to be all leaking past the rings and into the crankcase. I could barely hold back the pressure from the breather line with my finger. From what I can tell from looking in through the spark plug hole, the cylinders don't look too bad and I can still see the cross hatching quite well. The only good way to see what's happening is to open it up, but I don't think the guy will go for it.


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## txsteve (Dec 4, 2011)

This might be going on with that engine also..It runs good on one cylinder either one but two cylinders runs bad and you said the muffler gets very hot..
The muffler might have a block in it..because one cylinder exhaust can get through it ok,,but 2 cylinders makes more exhaust flow travel that the muffler can't handle it..


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## Country Boy (Mar 18, 2010)

That's something I can definitely check into. The exhaust system is a two piece setup with the exhaust manifold dumping into a muffler mounted under the frame. If I pull the muffler, I can see if it runs any better. Thanks for the suggestion!

The exhaust pipe was glowing right where it dumps into the muffler, but the rest was not.


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## Country Boy (Mar 18, 2010)

The exhaust seems open, and I can blow compressed air through the muffler with no issues. I wrapped the blowgun in a shop rag and stuffed it into the opening, and blew air back through the muffler both ways. The air was coming out the other end quite well. Either way, I spoke to the customer and he doesn't want to stick any more money into the unit. He said he will just run it until it blows up and just get a different one. He got 11 years out of it and feels that is good enough. Such a shame because the tractor is in excellent shape (Ariens 1742), but its his decision I guess.


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## jhngardner367 (Apr 5, 2011)

Run it without the muffler,and see if it still gets red,or if the wire being off still affects it.If the wire being off still affects it,it could have a bad side in the coil.They use the "wasted spark "system,where both fire at the same time,so a weak side could cause it to load up,and dump extra fuel into the exhaust,causing the glow,and rough running.Taking off one wire,causes a stronger spark in oneside,and it smooths out. I had the sameproblem on one, in a Craftsman. It also thins the oil,so that could have caused the governor problem,too.


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## Country Boy (Mar 18, 2010)

Never thought of trying a different coil. I did run it without the exhaust, no change except it being very loud. :laugh:

The guy refuses to stick any more money into it, but I will mention that it may be a coil if he ever decides to try getting it running better. His neighbor is good at fixing stuff, and he collects and rebuilds Cub Cadets. I might mention it to him as well in case he ends up looking at it for his neighbor.


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## txsteve (Dec 4, 2011)

Did you ever find out the problem yet or abort.?


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## Country Boy (Mar 18, 2010)

Customer didn't want me to spend any more time on it, so we stopped where we were. Its up to him if he wants to look into it more in the future.


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