Carbeurator Accelerator Rod boots

C

CDory23

New member
I've been chasing a low Vacuum issue with my Twin Yamaha 40hp outboards. I've replaced all gaskets and gone through the carbs a few times.

I noticed today finally that most of the Accelerator Rod Rubber boots are in horrible shape and even created a bit of corrosion in that whole general area. I"m wondering if this could be the cause of a low vacuum?

I also can't seem to find that part for sale, and can't see how these actually get replaced.

Anybody replace these before and think this part could creat this low vacuum issue?
 
CDory23":h3te6m0j said:
I've been chasing a low Vacuum issue with my Twin Yamaha 40hp outboards. I've replaced all gaskets and gone through the carbs a few times.

I noticed today finally that most of the Accelerator Rod Rubber boots are in horrible shape and even created a bit of corrosion in that whole general area. I"m wondering if this could be the cause of a low vacuum?

I also can't seem to find that part for sale, and can't see how these actually get replaced.

Anybody replace these before and think this part could creat this low vacuum issue?
Click to expand...

If that is # 19 in the pict. that looks like a dust seal to me.
What is low vac? How many inches at Idle, How many hrs? have the valves been adjusted / checked? How doe's it run at Idle? Check compression @WOT (Throttle held open all plugs removed) Have a good one.
 
Well I salvaged 3 decent boots between the two motors so I could put together a carbuerator assembly and test. It helped a lot. I had hardly any vacuum , maybe 5cm hg before and now I have 24cm Hg which is 9.4 inches Hg. I still feel that is low but the engine is running very well, quiet, doesn't shake, revs up fine, Vac synced.


I tested Compression last week and its 180psi +/- 5% each cylinder on each engine.

Engines have 750hrs. I have not checked clearance, I feel the engines are pretty low hourage for that but maybe I should.
 
CDory23":10axate8 said:
Well I salvaged 3 decent boots between the two motors so I could put together a carbuerator assembly and test. It helped a lot. I had hardly any vacuum , maybe 5cm hg before and now I have 24cm Hg which is 9.4 inches Hg. I still feel that is low but the engine is running very well, quiet, doesn't shake, revs up fine, Vac synced.


I tested Compression last week and its 180psi +/- 5% each cylinder on each engine.

Engines have 750hrs. I have not checked clearance, I feel the engines are pretty low hourage for that but maybe I should.
Click to expand...

Is the vac. test port on the throttle body of each carb. or right on the intake? If on the carb crack the throttle up to 1200rpm & read your vacuum. That compression is great! If it runs that well you must not be reading vac. @ the manifold I would think 18 in or so?
Good luck with your project :mrgreen: :beer
 
Back
Top