Tom Jones

My Feedback: (4)

Is there one and if there is what is it made out of? Vitron or ? Is it flat or an O-ring? Thanks for the Help, Tom

SrTelemaster150

If you are speaking of the manifold/head joint, there are aluminum ring gaskets but I have not found a need to use them.

There is an "O" ring between the carburetor & manifold.

blw

My Feedback: (3)

I haven't tinkered with a 150, but other Saito manifolds have either a flair or raised bumps to apply pressure to that aluminum washer. The aluminum washer presses in on the o ring when the carb is tightened down. I bet a lot of older 72's wouldn't run without those washers.

SrTelemaster150

In the FA150/180 (& probably the 120) there is just a smooth finely finished flat surface in the head. The steel insert of the manifold mates W/that surface. It too is a very smooth surface. The addition of the the aluminum rings just sounds like something to fail & cause problems so I stopped using them long ago.

Judging from the low reliable idle I get from my tune, it seems that they are not really needed. YMMV

blw

My Feedback: (3)

Not meaning to argue with you Senior as I don't have a 150 to look at like you do, but I looked at a 56, 72, and 125. The aluminum rings seat down inside of the intake opening and are the same diameter as the o rings. They do have a purpose on these engines.

You can see the purpose on an older, unmodified 72 when fixing the old backplate problem. The backplate flexes and the manifold applies and relaxes pressure on this part intermittently, causing the engine to run lean.

I'm sure some engines run forever without them.

Tom Jones

My Feedback: (4)

BLW, I have neither the O-ring nor the metal ring gasket. Does the Oring go into the head first and then the metal ring,then the intake manifold? I bought the engine used and I could not get any information from the exploded views in the manual. Do they all come in the carb gasket kit? Tom

SrTelemaster150

The intake manifold on the large single cylinder Saitos have no "O" rings other than the one between the carb/manifold.

The manifolds of the 150/180 are cast aluminum W/a steel insert @ the head interface & are not attached to the back plate either. It is clamped very tightly W/a ring nut similar to the exhaust nuts on most Saito engines. Now that I think of it, the 120 might be attached to the backplate & has a tube, not a cast manifold, so it is probably entirely different..

I have several of the aluminum gaskets from gaskets sets & new engines. If I ever experience idle or other induction related problems, I'll give them a try. If it ain't broke you can't fix it.

Funny thing is, although they send the gaskets W/a new engine, I don't recall finding one in a new un-tampered with FA150/180. I've had a pair each of 150s & 180s that I bought new. I did however find a dislodged aluminum ring in an intake port of my tired old 150 when I completely dismatled it recently. It has been dismantled several times & I probably put that gasket in there myself back when I concerned myself W/using them.

w8ye

My Feedback: (16)

The later 120S versions had the intake manifold made just like the 150S.

The first design 120S has the twisted tube intake.

I don't know about the old style original straight 120? I think it was made a lot like the the 150S but was a different size?

SrTelemaster150

There is no "O" ring on the 150 where it goes into the head & the aluminum gasket is optional & I have not found 1 in a new engine that I have taken the manifold out of.

Why are you concerned?

Does the engine run OK?

SrTelemaster150

Yes the medium sized Saito singles have a tube type manifold W/an "O" ring. It is held in the head by the tension of the tube that is secured tightly to the back plate.

My FA91S is like that.

In fact, the gasket set for my 91 had the viton "O" ring for the manifold/head interface labled as such.

The 150/180 are entirely different.

SrTelemaster150

OK, here is a carburator gasket set for the old half-round cam cover FA150. (not the new high case "B" model)



Clockwise from bottom left:

"O" ring for the carb/manifold joint
2 small "O" rings for the spray bar
Aluminum ring for the manifold/head interface (Your engine probably never had 1 of these in the 1st place)
Not sure about this one, but I think it is for filling the gap when eliminating the choke plate (I need one of those)
Teflon ring for use W/the choke plate.

The only other gaskets for the 150 are for the rocker covers, cam cover & backplate.

If you have your heart set on 1 of the aluminum gasket rings, send me a SASE & I will send you some, I don't use them.

There is no "O" ring for the manifold/head joint!

SrTelemaster150

Double post

blw

My Feedback: (3)

I have a 91 out on the bench and I forgot to look at that one.

SrTelemaster150

There is a viton "O" ring @ the top held in by a ridge on the manifold tube & a regular "O" ring (same size) @ the bottom.

No (sepearte) rings to press the "O" rings.

I think the 65 & 91S are the oldest designs of the current Saito line.

The backplate is the ket to the whole assembly. The carburator is mounted directly to the backplate W/the manifold tube captured between the carb & the head.

Entirely different system than the big blocks.

I was swapping 3 different carbs back forth on my FA180HC tonite. The big blocks only require loosening a ring nut just like the exhaust pipe. I have nylon ball sockets in the throttle linkage so I can swap a carb in less than 5 minutes.

Hobbsy

My Feedback: (102)

Here is a shot of an extra one I have, I use it because the engine is designed that way. It goes in the intake port and the black end of the intake pipe holds it in place.

Tom Jones

My Feedback: (4)

Sr, thanks for the offer. I was just looking for things that might be amiss. Just cant get this engine fired up. I've cleaned out the carb, adjusted the valves, checked all the fuel lines and clunk. I know the fuel is good as I've run other engines with it, got a new f-plug. Don't know what else to try. Any suggestions would be appreciated. Tom

rv9-a

If you do not have one you can get a manual in PDF form from Horizon. The part you need is listed in the exploded view as #91, the specific part number for your engine is
150S91A. Get this gasket set and I'll bet your engine will run just fine.

I have had several Saitos thru the years, FA56 to FA180, I believe they all had the o ring and the backing washer. One of my current engines is a FA 82a it has the gasket set installed (from the factory) and runs great.

Good luck

Tom Jones

My Feedback: (4)

RV-9, Thanks, I was thinking that that was what I should do, but I just hate to spend more in shipping than the parts are worth. Such is life. Tom

rv9-a

Try ordering them from your LHS. Sometimes they will not charge you shipping, especially if it is included in a larger store order.

Hobbsy

My Feedback: (102)

The aluminum washer and O ring arrangement is only up through the 1.25, The 1.50 and 1.80 have the arrangement I pictured above, the 2.2o has three bolts holding the intake tube onto the head. Here is a shot of the .62a washer and O-ring, the .40a has a completely different arrangement.

blw

My Feedback: (3)

The 30 is different too

SrTelemaster150

OK, I went up & inspected the intake port carefully on my new FA180.

It took some picking W/a hooked x-axto knife blade, but yes, there is a metal gasket in there. it was stuck pretty good to the port face.

The fact still remanis that I have successfully run my other big blocks W/O the gasket getting 1,000-1,200 RPM stable idle from the FA180HC W/EI. There certainly doesn't seem to be any leaking going on there.

I have several of them around & if I ever run into problems W/a particular engine I will put a gasket in there, they don't really seem to be necccessary from my experience.

The machined steel on machined aluminum joint under substantial clamping pressure will make a seal.

Case in point? VW air cooled flat 4 boxer engines have no head gaskets & rely on the same type of machined steel/aluminum joint.

And again, there is no "O" ring in the 150 head manifold joint!

SrTelemaster150

Your LHS probably sends in an order to Horizon once or twice a week. they should gladly add your parts to their order & not charge you shipping.

As far as the gasket? I think that even W/O the gasket there should not be enough leakage to prevent starting. The steel/aluminum joint will seal in most case & if it is leaking enough to prevent starting, a anotyer aluminum surface in the joint proably won't cure the problem.

Check to make sure you are getting fuel delivery to the spray bar.

Make sure your manifold nut is tight. Place your finger over the muffler, open the throttle & turn the engine over several revolutions.

You should see fuel dripping from the carburetor. If you don't the problem isn't the lack of the gasket ring.

BTW, the gasket ring may be in the port after all. Use a pick & slide it outward fro the prot runner to see if you feel it catching on the edge of the gasket ring. Mine was stuck & it was not obvious to the naked eye. If you feel the pick catching on something, the gasket ring is most likely there. Be careful that you don't scratch the sealing surface.

Hobbsy

My Feedback: (102)

Dan, this my Saito 1.50 carb mount with two layers of Teflon Plumbers tape, the washer is already in the intake port.

SrTelemaster150

I use the teflon tape on the muffler joint & (non nut secured) exhaust pipes but never on the intake or muffler nuts.