Perkins AD3-152 lost power

Hi,
I could use some advice on a '78 30B with Perkins AD3-152. I was using it over the winter cutting some firewood. It was idling and all of a sudden it started making an unusual sound out the exhaust. It lost nearly 60% of it's power too almost like it's running on one or two cylinders. Upon further review, it seems to be making a huffing sound out the intake? No unusual white smoke out the exhaust or bubbles in the radiator which would say it's a head gasket for sure. I pulled the fuel tank and valve cover. The valves could use an adjustment but nothing extreme and all the valves are opening and closing fine. If one of the valves was hanging open the tappet clearance would be excessive and this is not the case. It use to start very easy. Another symptom is now it takes a lot of effort to get it running and when it does, there is hardly any power. One other thing I noticed is the valve cover and rocker valley of the head are painted with Glyptal paint. Did Perkins do this in the factory or is this a sign the engine been rebuilt at some point?
While I think I know where this is going and before I pull the head and all the fun that can lead to, I thought I'd get some input from the group here. If there is an easy way to get the head off due to rust and carbon build up, please let me know.
Thanks for any and all advice in advance.
Best regards, C3

I'll bet it's the head casket
mine had the exact same symptoms about 3 yrs back and I would have bet the farm it was a valve problem as well
Head was no trouble to remove and clean up
Head and valve cover casket was cheap i think about 15 bucks for both
Took about 3 hrs total to due runs great
I've been told that perkins 3 cyl's are hard on head gaskets but on two tractors with the a3-152 in them over 10 yrs of use its the only time it ever failed me
I put about 200 hard hrs a yr on each of them
Let us know what you find out

I agree, it is probably a blown gasket between the cylinders.....not a real common problem but it does happen.
.......Sam

Thanks for the response. I read a lot of posts before I created this one and I was thinking head gasket too.
With all the dirt build up on the valve cover and head, I'm thinking the engine has never been rebuilt, so I guess Perkins did apply the Glytal to the rocker valley and valve cover?
I'll keep you posted.

I had the exact symptoms on my MF-MF-205 a few years ago. It has the same engine. I tore it down and it was a blown head gasket. A small piece was missing between two cylinders. The specification calls for replacement, torquing, running and retorquing. It is challenging to remove fuel tank, valves and head twice for retorquing but I did so. I suspect the previous owner did not and this was the cause of the blown gasket.

I rigged up an old Briggs & Stratton gas tank to warm the engine up enough to re-torque the head bolts.

What's the recommendation for a head gasket on the AD3-152, the copper style with spray coating or the grey/black style?
Thanks,
C3

I used the copper style with spray under the assumption that it would hold up better under compression. So far so good.

I would have been inclined towards the copper gasket, until I found out the turbo charged 3 cylinder Perkins used the other type.....must be better?.......Sam

Thanks Blue Water Massey, when you read the threads on this forum, you hear a lot of folks replacing the head gaskets on the AD3-152's as you said. I figure if I can get another 36 years out of the new one, I'll be good. Got my fingers crossed....
Making room in the shop so I can tear into it further and pull the head. I'm a little concerned the head will be tough to get off after 36 years, but you don't know till you do it.

I was able to limp the 30B to the house for teardown. You guys were spot on in your assessment of the problem. The pic says it all!
I was sweating the head being stuck due to carbon build up but is came right off. I was very surprised.
Cleaning things up now for when the gasket set arrives.
Thanks to all of you for your help!
I'll let you know how it runs when it's back together.
I'll be searching the forum for assistance on cleaning the injector cleanings. Any advice on this?
Thanks,
C3

Here's the pic.

SUCCESS!
Installed the new head gasket yesterday and it fired up real nice and easy. Runs smooth and strong like it use to.
It won't be fun pulling the valve train off and injectors to re-torque the head, but I see that in my future.

Thanks for your help! It is greatly appreciated.
C3