Do I have to pull the engine?

[Joker]

I have a '97 Argo Response with a 18HP B&S Vanguard. The engine has never ran consistently and I think I have it narrowed down to leaky rings in the front cylinder.

I don't like the thought of pulling the engine for several minor reasons (not completely confident in my ability to get it back in, projects always get more involved - never less involved than originally expected, etc...)

The front cylinder seems to be the culprit and it looks like it might come out without pulling the engine. Does anyone have an opinion, or better yet, experience with this?

The rear cylinder quickly gets to 150psi while the front one takes some revolutions to get to 100. If I pour some oil into the plug hole, the cylinder produces 120psi with some coaxing. I am thinking about putting new rings and a head gasket in the front cylinder and seeing if that fixes the problem. (Oil spraying out of the breather valve, lower than expected power.)

Thanks in advance for any responses.

J

[Roger S]

The cylinders are cast as part of the block, so the engine would have to come out.. not as hard as it looks once you start.

Even though you're talking about blow by, I'd check the valve clearance. They're known to get tight. Put it at TDC of the compression stroke. Then use a pencil, etc stuck in the plug hole resting on the piston, move the piston down the bore a 1/4" after top dead center. Set the valves at 5 thousandths.

[LarryW]

Pulling the engine isnt that bad. Just 4 bolts, few wires, fuel line, belt, exhaust and throttle cable. I would pull it if your doing any internal work because of the fact it would be easier to do and also easier to make sure everything is clean. If you do it in the argo, if possible, you have a bettter chance of getting dirt or other debri in the engine when its apart. It cant take more then an hour to pull it out and if it does big whoop. Just my 2 cent.

[eightwheeler]

Ive been through this a few times and i do not pull the engine, instead i split the body and take the upper off, it gives you chance to check out the rest of the machine as well, and yeah its common for the vanuards to get blow by, easy fix though

[Joker]

Thanks for the good pointers. I never thought about splitting the body. And it sounds like removing the engine isn't all that involved. I guess I'll pop a beer and walk around the Argo until I decide on which direction to go (my version of flipping a coin).

I was originally hoping that the problem was just a valve adjustment. It was one of the first things I checked. Sure enough, all four were at 0.010-0.015". Once set to 0.005" it ran better, but still not great and progressively got worse. Eventually, I ran it with the air cleaner off and quickly ended up with a lot of oil on the windshield. I sucked some of the oil out of the engine to be sure it wasn't overfull and it still sprayed oil. So, I went and bought the compression tester which suggests a leaky cylinder (or head gasket). So, I figure that before Ice season starts, I should freshen things up in there and hope it fixes it.

Thanks again for the great ideas!

J

[Roger S]

If you fix it, yank the engine out and set on the bench. I have a '97 response, and can't imagine working on it in the argo. We spend more time thinking about it than doing it. One afternoon I walked out and jerked the 18 out of mine, was tired of the weak, low compression, valve floating, stock vanguard.. although it was in normal condition.

[Joker]

I'm convinced. I have decided to split the body AND pull the engine both. That way, I can fix the engine and check out chain tensions, clean the tub, etc.

I was just planning on new rings and head gaskets. Are there other things I should do while the engine is on the bench?

RogerS, you mention valve floating. Is there a spring kit or something I should think about getting? Is there a good place to order B&S parts (rings, gaskets, valve stuff) from?

Steve

[Roger S]

If you just want to work on the front cylinder, you could pull the front head and side cover. If you have the time and ability to go through the whole thing, I'd strip the block.

The stock valve springs are fine at governed rpms.. I had been running ungoverned and the valves will float at 4500 ish. But they were designed to float.. a built in rev limiter. If you are staying stock there's no need for better springs and retainers.

If you're interested in more power, the compression can be raised in the 18 by using a stronger, longer rod, which will also make it safe to rev higher, then the springs and retainers come into play.

I bought aftermarket performance parts as well as OEM briggs parts from Tennessee, where my briggs guru works.

Edit: I told a fib earlier, vanguard valve lash is known to get loose, which will make the compression release ineffective and can cause hard cranking.

[Joker]

Thanks again for the pointers. I am looking to keep things stock which will hopefully translate to reliable.

It took most of the day, but I got the top half of the body off today. Most of the time was taken in getting all the wiring disconnected from the top. Some of the switches didn't want to play nice.

I am thinking now to take the engine to a repair shop and have them fix it while I clean up the body and accessories. There is a lot of rusty bare sheet metal that needs cleaned and painted.

J