Briggs Intek Twin, left cylinder dead?

[Arkie]

Briggs Twin Intek
model 407777,
type 0174-E1

New to me engine, left cylinder dead, has spark, valve lash ok, compression 140.

Has the nikki 791230 dual throat carb. Removed the carb after checking all of the above 1st.
Removed the carb, installed another old used dual throat type Nikki just to see if any change in results.

Results: Now after the carb swap the left is OK, right cylinder dead.

Nikki carbs can be a pain sometimes.




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[KE4AVB]

So you just one dirty carburetor for another one.

Nikki are not that bad to repair, just got to understand Japanese instead of understanding Chinese.

[38racing]

at least you are working on one carb. my Tecumseh vtwin has 2 carbs

[Arkie]

So you just one dirty carburetor for another one.


Nikki are not that bad to repair, just got to understand Japanese instead of understanding Chinese.

At least swapping the dual throat carbs let told me that it is definitely the carb and not a leaky or cracked plastic manifold. The left cylinder was COMPLETELY dead at both idle and high speed with the first carb making me doubtful that it was the carb.
Price of them little bitty o-rings is depressing and they are all bad on the first carb.. (and buying a $15 kit is no assurance that all parts/pieces needed is in the kit especially correct size o-rings)
Was going to take two carbs and maybe make one. They are not the same inside.

Maybe time to get another understanding of China by trying a clone for $20

New OEM is around $200+

I took 3 of these types awhile back and made one but I'm now out of OLD dirty Nikki carb parts.

[KE4AVB]

Yes $0.70 ea is a bit high for them. At least they are available you could be buying the jets if Briggs had their way.

[Arkie]

Installed a NEW Nikki dual throat CLONE on this twin Intek and got a good run EXCEPT
every once in a while (erratic and intermittently) usually at lower rpm it would spit back through the carb.
Idea: maybe i could see which cylinder a valve is not seating if I watched the dual carb throats carefully as to get a hint as to which cylinder is spitting back then check valve seating on that cylinder. (if valve lash ok then would be time to remove the head for closer inspection for a sticking valve or bad valve seating.
I moved the machine into a darkened room and started watching the carb air intake and sure enough I seen orange spit back on the right cylinder intake side. Long story short the valve lash was at .001-.002 on the exhaust AND the aluminum/steel push rods were on wrong valves rockers.
When I swapped the push rods (aluminum on intake) the valve lash on the intake went from .008 to minimum (.002) and the exhaust to .008.
Was little bit concerned that just setting the valve lash would get a good seat seal if the engine had any many operating hours of carbon buildup on the seat.
Set valve lash and all ok.

Appeared Bubba had been in that vicinity before and when carb failed it helped save the engine and the valve/seat.

[SUKI]

Boy having undo work like that but seems more and more it is coming into the shop lately. Usually end up having to charge more for the job order.

[Arkie]

Boy having undo work like that but seems more and more it is coming into the shop lately. Usually end up having to charge more for the job order.

Yes, going in behind where some people have been messing around just makes repairs and troubleshooting harder/more challenging and time consuming.

Just got through putting a old, but nice clean looking Briggs twin L-head back together from parts in a bucket that a guy had taken off both heads because it would not start. He would have went further but he could not remove the flywheel.
It had a bad ignition magneto was why it would not start and run.

[38racing]

there's a Briggs engine that actually has the aluminum push rod on the exhaust. mechanic girl I know once told me her boss told her she had it wrong and she showed him the manual for the engine which showed the aluminum on exhaust. It's because the acr is on the exhaust on that engine I think. maybe check your manual.

[Arkie]

there's a Briggs engine that actually has the aluminum push rod on the exhaust. mechanic girl I know once told me her boss told her she had it wrong and she showed him the manual for the engine which showed the aluminum on exhaust. It's because the acr is on the exhaust on that engine I think. maybe check your manual.

I had looked in the service manual for specs using the model number and I had checked the left side valve lash first few days before when I found that cylinder was dead and seen the aluminum on the intake.

Good info about some aluminum push rods on the exhaust side I was not aware of that. (and have not seen a service manual for a Intek Twin OHV that ever indicated such) I'll note that in my existing service manual as a heads up.

Another good point about telling a woman she is wrong.
I would NEVER EVER DO THAT. (even if I knew she is wrong)

Thanks for that info.