M151 Engine Sputter Question

[carolinamv]

I got my '65 running and driving on the road now.

It runs strong and well up and down hills, doesn't want to shut off or anything, but when its running you can hear a slight sputter from the tail pipe and a little small back fire.

I put a couple new spark plugs in even though they all looked clean , cleaned the distributor the best I could, its getting plenty of clean fuel , the new carb is on tight.

Could it be a timing issue? Im not sure what to check next. Im trying to get it parade ready for my wife for the 4th of July parade.


Also, it had no brakes, I bleed the brakes well , put new DOT 5 in , brakes work great but I dont have a brake light. New bulbs installed , could it be the switch ? Im hoping its not wiring.

[HILLBILLY-06]

On the engine, it's possible you may have a vacuum leak someplace, I found a bunch on mine, all those little lines with fittings on them, were all leaking. could also be that exhaust manifold, sometimes they leak a little there.

As for the brake light's, you need to check for voltage in a couple places, one at the brake switch under the dash, the other at the light plugs in the rear. You can also check for voltage at the trailer receptacle plug in the rear also, it's easy to check there & you don't have to disconnect anything to do it.

Hope you find out what it is, I'm sure there will be some suggestions from folks on here that know plenty more than me...

[carolinamv]

I read it could be the intake manifold gasket? Ive never replaced one before but I think I can try that next weekend. I tightened up the carb real well so I don't think it can be that.


I will try the brake light ideas next Saturday also. I have a tail light and head lights.

I sure want to get it running just right.

[rickf]

Since you have no history on the engine the best thing to do is a complete tune up from start to finish. start with valve adjustment and then points adjustment if you have them an then timing and plugs, all of them pap, rotor, and at least check the wires if you don't replace them. Once all that is done then you can set the idle mixture screw on the carb. If you are still having problems set the idle up to a high idle with the hand throttle and spray some carb cleaner all around the intake manifold to see if it changes the engine speed at all. If it does then you have a vacuum leak. If it is running and idling good I would say the carburetor does not need to come apart. The other thing that was mentioned is exhaust leaks. These exhaust manifolds tend to leak and that will cause small backfires when letting off the gas if that is what you are hearing.

Rick

[carolinamv]

Rick , Whats base timing on the engine?

I has a new carb, spark plugs, rotor ,checked wires,I played with the idle screw on the carb with no change other than the idle. it idles and runs fine except for the sputtering and slight back fire time to time. I sprayed carb cleaner around the intake manifold and it does have a slight increase in RPM.
Should I order new intake manifold gaskets and try and replace that ?

[rickf]

The timing is 6 degrees but the timing marks are set for that already. All you do is line them up and you are good to go. The idle screw I am talking about is the idle mixture screw, it sounds like you were playing with the idle speed screw. If you did that vacuum test with the air cleaner hose on then you have a vacuum leak. Before buying a manifold gasket make sure you do not have a line off or broken. Go back and squirt short sprays in small areas until you have it narrowed down to one spot where the engine changes every time you spray there and then see what is there. If no hoses or lines then you need the gasket that is there.

[carolinamv]

Where is the idle mixture screw located? I can try that tomorrow.
I ordered new manifold gaskets today just in case.

On the drivers side , there is a fitting/hose coming from the valve cover, I don't have anything on that. I just have the fitting from the valve cover. How can I upload a picture?

[carolinamv]

[img][IMG]http://i1052.photobucket.com/albums/s451/BulldogMack13/m151-engine.jpg[/img][/img]

I circled the part Im talking about on a picture I found online. In the middle I put a read dot on where my line is missing , I just have the part that comes form the valve cover and nothing past that dot.
Do I need to connect that to something?

[rickf]

Do you have the parts that come out of the intake manifold? That is your PCV valve and yes that all needs to be hooked up before you try to do any more adjusting. The idle mixture screw in on the carburetor base flange that mounts to the manifold. Looking from the drivers fender it is just to the right of the top bolt and possibly under a plug. You can't do anything with that before fixing the other problem first though.

Rick

[carolinamv]

No I don't have any of that after the fitting that goes into the valve cover and nothing from the intake manifold. There might be a plug in the manifold but I don't remember.

Do you know where I can get the parts to assemble that? I guess I need them pretty bad. I wonder who took it off and why.

Mine is a '65 M151A1 if that helps

Also will it hurt it to drive it around in its current state?

[carolinamv]

[img][IMG]http://i1052.photobucket.com/albums/s451/BulldogMack13/WRA/a.jpg[/img][/img]

I guess I need everything I circled in red?

The next is a fuzzy picture of my engine.

[img][IMG]http://i1052.photobucket.com/albums/s451/BulldogMack13/CAM00463.jpg[/img][/img]

[rickf]

Yes, you pretty much have it right. You do however have a fairly rare flat top air cleaner. Get some clamps on the air cleaner to carb hoses, that may be where you where picking up the signal of a vacuum leak. With all of the stuff that is not on there and yes the manifold is plugged, it should run OK. At this point though you have NO crankcase vent at all so you are going to be blowing oil out of seals, most likely the rear main seal.

[rickf]

OH, As far as finding all of the tubing. You can make up most of the stuff that goes around to the other side. The fittings for the carb and manifold are going to be a little tough to find. Contact Fil Bonica on here, he has been coming up with a lot of that stuff. He may even have the lines used and then you would not have to bend them.

[carolinamv]

The place the crank case vents is from the intake manifold or where the PCV valve goes between the valve cover and intake manifold?

I do have a very small leak from the rear main.

I just sent a guy on the forum some money for all the tubes,fittings,PCV valve , well, the entire set up.

[carolinamv]

When replacing the manifold gasket with the correct gaskets, would you use permatex also or just the gaskets that are correct for it?