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Engine
Submitted By: fixb52s
Date Created: 04-18-2007
Description: The 8 HP engine runs, but needs work. I have a 3.5 HP engine from a broken edger that was going to be installed, but I found this 5 HP engine for a good price.
Related Projects: Manco Dingo Go Cart
    Tear down
    Frame restoration
    Pedal stops
    (Engine)
    Reassembly
    Rear axle
    Floor mat
    Tires


Old engine
The engine needs some work. A new shroud and a pull start assembly is needed, and a different engine plate is required. The clutch is also bad and requires a 1" shaft unit. A newer engine will be better here.

This engine came off a Sears edger that was parted out. It has very low hours and runs great. But it's only a 3.5 HP so......
Small engine


New 5.0 HP
I found this 5 HP Tecumseh OHV engine on ebay. It was advertised as having less than 1 hour of use. I sold both the other engines on ebay to recoup the cost of this engine.

Before firing up the engine, some things must be done. The fuel tank is flushed, and the fuel and breather lines are replaced.
Go through


Cleaning the ignition
Since the engine sat, the flywheel and magnetic triggers have some rust. The magnets and coil contact are sanded to clean off any rust and ensure a strong spark. The air gap for the coil (the distance between the flywheel magnets and coil) is also checked. The best gap tool for this is a business card. The thickness of the paper is the perfect measurement, and it can contour around the flywheel.

After the engine was put back together, it started on the first pull, but was surging bad. This is a well known problem with Tecumseh engines that occurs when the carb gets dirty. Gas sat in this carb for some time, and it was gummy inside, and some solid deposits formed. This is the carb disassembled. The red pin is the main jet, and the float is also seen.
Carb rebuild


Main body
These carbs must be properly rebuilt, and that means CLEAN. The main jet (white arrow) comes out of the center bore (yellow arrow). There are 2 o-rings on it that must be replaced. ENSURE the lower ring is removed. It is easy to miss this, and if not removed, the engine will never run correctly. A hooked paper clip will get it out. Also, the needle seat must be removed, again, with a paper clip. Do not scratch the carb with the clip. The red arrow points to where a welsh plug is located. It has to be removed to get the carb clean. New welsh plugs come with the carb kit. A Q-tip works good to get the hard to reach areas clean. If the carb is very dirty, the body should be soaked in a carb cleaner overnight to get all the small passages clear.

This carb is not adjustable, but the metering jet can be removed for cleaning after a plug is removed (red arrow). The small passage must be cleaned with some cleaner, and should be blown out with compressed air. The carb also has a series of precision drilled holes (black arrow) that must be clean. There is a welsh plug covering this, and it must be removed for access. Clean them with a toothpick, never use wire because if these holes become enlarged, the carb will need to be replaced. The yellow arrow points to the primer bulb area. The bulb should also be removed for cleaning, and a new one installed.
Side main body


Engine installed
The engine runs great and is installed on the frame. A correct throttle bracket from a Tecumseh Power Sports engine replaced the slide control so a throttle cable can be used.

The engine came with a clutch. I will not know if it works until I get it running, but it appears new and in excellent condition. A little WD40 and some engine paint makes it look better.
Clutch included


Goodbye clutch
After some thought, I decided to just go ahead and get a torque converter. A torque converter is nothing but a varable speed transmission that changes a belt position from two pulleys. Low engine speed results in better pulling power than a clutch, and changes to a lower gear ratio as speed increases. This is a Comet Torq-A-Verter I got from GoKartSupply.com (a local company for me, so I was able to pick it up directly). The nice thing about this cool setup is it is self contained. Instead of the jackshaft setup Manco supplied that mounts under the engine, this has it built into the main plate.

Here is the plate installed on the engine. It is quite a thick piece of alloy, so the jackshaft will not flex unlike the earlier designs of this unit.
Bolted on


Aligning up the chain
While installing the axle, the chain is aligned with the rear pulley to ensure a proper mesh.

The front drive pulley and belt are installed and torqued down.
Bolted together


Cover trim
The cover is marked for the chain to pass through and cut out. It is then bolted on, completing the drivetrain.

This Enduro engine was set up for power equipment, and had a hand control. A throttle control from a Power Sport engine was installed so the engine can be controled by the pedal. A on-off switch was also added to shut it down since the old control had this built in.
Throttle control

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