Log Splitter engine

[Roy_N]

I’m looking for advice on replacing or repairing an engine on a MTD 20 ton Log Splitter. I bought the splitter new in 2004 and it came with a Briggs & Stratton 5 HP model 128702. By 2007 the engine became very difficult to start. Figuring ethanol or stale gas in the carb was the problem I rebuilt the carb, but that didn’t help. But when I replaced the carb it worked fine. By 2008 the engine was leaking lots of oil, and having never rebuilt or taken apart an engine, I decided to replace the engine and save the old B&S for a later day to tear apart, see how these things work and look inside, and perhaps rebuild it. I still have this engine in my storage shed.

So in 2008 I installed a B&S 6.5 HP 675 Series Quantum Model 126T02 which cost about $170 new. I had to cut the 7/8” dia crankshaft to the 1 13/16” length and cut a new keyway, but other than that the engine dropped right in and worked fine for several years. But by 2011 it too was now hard to start. I replaced the carb, air filter, spark plug, and primer bulb. Nothing helped. In hindsight I probably should have replaced all the fuel lines. Presently I have to remove the spark plug and spray in some engine starting fluid, for the engine to start. And even then it takes about 15 pulls of the cord to get going, whether or not I use the priming bulb. And the recoil of the pull cord can be real nasty, which I presume is because this engine is probably designed for a lawn mower with a blade, and the engine itself doesn’t have a heavy internal flywheel. When I shut off the now warm engine, which has run for about 30 minutes, and let it sit for about 10 minutes, when I return the engine won’t start unless I use the starting fluid spray – just as if I let it sit for a few days.

Because of the nasty recoil issue and difficult starting I’m considering replacing this B&S engine with a $95 Harbor Freight Predator 5.5 HP 173cc engine, or a $153 Honda GCV160N5A 5.5 HP engine.

Your thoughts?

[bgsengine]

First Thought: Take that starting fluid and throw it away. Starting Fluid (Ether) is for DIESEL ENGINES without glow plugs. It will very quickly destroy an ordinary gas engine. If you got to use a starting aid, use *Carburetor cleaner*

As you have discovered, starting fluid will kill a small engine.

Second Thought: Go for the Honda - it's pretty much the same engine as the HF one, BUT , you have Honda warranty on it, and Honda's Quality Control behind it. Unless of course you plan to ignore my first piece of advice , in which case, but a couple HF engines since if you are going to use starting fluid, you'll be replacing the engine every couple years.

[KE4AVB]

First the best starting fluid is the regular fuel that the engine uses; starter fluid is for diesels and even they become dependent on it. The use of starter fluid can damage your engine as it washes away the lubricating oil in the cylinder at start-up also the engine be become dependent on it. Since you have been using starter fluid to start it I would do a compression test to see if you still have good compression.

Your starting issue may very be the primer system on the 126T02. On these the air cleaner gasket can not seal if the air cleaner base gets warped from over tightening the mounting screws. Sometimes you can cheat by adding a second gasket to get to seal; other times it requires replacement of the air cleaner base. Either way it got to be sealed in order for the primer to push air into fuel bowl to prime carburetor.

On the replacement engine you would need an engine designed to operate without additional weight of a blade such as one the would operate a pressure washer if you wish get away that nasty kick back.

[Roy_N]

Okay on the starter fluid, it's carb cleaner from now on.

Yesterday I removed and cleaned the carb. Everything looked okay, but I cleaned all the orifices and passages, and changed all the gaskets and seals anyway. The thin rubber type material air cleaner gasket was replaced with a thicker fiber gasket. I checked the passages between the primer bulb to the carb and all were clear. I also changed the primer bulb and made sure it was seated. Yet when I plunge the primer bulb a few times no gas gets squirted up the main fuel jet into the carb opening. Then I took a small bottle of compressed air with a small extension tube, the type used to clean electronics, and put the tube into the vent hole of the primer bulb, and gave the bottle trigger a quick squeeze. Lo and behold, gas is squirting up and out of the jet like Old Faithful. So I know the passage is clear. I plunge the primer bulb again with my thumb a few times, and no fuel appears. Okay, I'm stumped.

When I do get the engine started, the engine runs just fine. No hunting/surging, no burning of oil, no thick smoke, spark plug just has a light gray residue and is not fouled. I did do a compression check and I got between zero and 3 lbs. Is automatic compression release a cause for this, or are the piston rings really that bad? Yet the engine runs fine once I get it going and it warms up a few minutes. I did find the carb cleaner worked best to start the engine when I removed the spark plug and sprayed directly into the combustion chamber. When I sprayed into the carb it didn't often help start the engine. I'm wondering if the rings are truly worn and thus not creating the vacuum needed to draw the gas fumes from the carb to the combustion chamber.

Though I'm going to replace this B&S with a Harbor Freight Honda engine knockoff, I sure would like to understand what is the problem with the B&S engine.

[KE4AVB]

I would have the test gauge setup tested on another engine. I had a gauge setup that the check valve became struck and would register the compression on even a known good engine. If the engine only had 3 PSI it would not even attempt to start the direct priming in my opinion.

It take somewhere around 30 PSI for engine to even attempt to run or at least that what the 7 Hp Briggs that I just rebuilt had. It would run slow with direct priming until the flooded condition cleared and then just die. It had a worned out cylinder (needed over sizing) and valve clearance issues.

The compression release does lower the compression quite a bit but not that much. You may have a sticking valve or ring problem. A leak down test should pin you to which area is the cause of the compression loss.

On the primer problem, take the air base and gasket off. Look at impression on the gasket left by the air cleaner base there is probably an area where there is little or no contact which is causing an air leak.

[Roy_N]

The air base and/or gasket seems to have been the problem. With a toothpick I applied a tiny bead of Permatex #2 non-hardening form-a-gasket sealant around the air channel of the base, then reset the gasket and reassembled. Using the primer bulb now sends gas up the carb main jet. However the low compression isn't enough to suck that priming gas into the combustion chamber. Maybe it is the rings or sticky valve, I don't yet know. But I can still get the engine running by removing the spark plug and give the chamber squirt of carb cleaner.

I was going to replace this B&S engine with a Harbor Freight Predator Honda knock-off. But unlike the B&S Quantum which has a relatively soft crankshaft that I did cut with a Sawzall, the HF engine has a hardened steel crankshaft that I can't easily cut to the length I need. And the HF engine without a heavy flywheel is designed for a lawnmower, and that would still leave me with a nasty starter cord recoil that rips the cord handle out of my hand. So I've done what I should have done in 2008, and that is get the Honda engine which is built for my application. Why I didn't do this in 2008 I can't remember. Anyway the Honda engine should be here Friday, but by then I'll likely have all the firewood I need for this season already split, but at least I'll be ready for 2014.

[bobodu]

You can cut ANYTHING with an abrasive cut off disk in an angle grinder !!! Much more accurately too.

[Buckshot 1]

What no one has used starting fluid with upper cylinder lube?