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Just identify your engine type and follow the link for full instructions.

Dismantling an Engine for Rebuild

Automotive engines

Motorcycles: two-stroke
Motorcycles: four-stroke

Cars and light trucks: Gas-powered
Cars and light trucks: Diesel-powered 

ATVs, skidoos etc.: two-stroke
ATVs, skidoos etc.: four-stroke 

Home and garden equipment

Our advice applies to all forms of engine-powered home and garden equipment. This includes:

Lawn mowers
Lawn tractors
Leaf blowers
Garden tillers
Edgers and trimmers
Chippers, shredders and mulchers
Portable compressors
Pressure washers

Click any of the above links and use the information there to identify your machinery's engine type. There are two types. The approach differs depending on whether your machine has a type 1 or type 2 engine.

Agriculture equipment

Agriculture equipment falls into three categories. Identify your engine type and click the link below to read instructions on using Engine Release to free your seized engine.

Agricultural Diesel engines
Agricultural Gas engines
John Deere horizontal engines

Marine engines

We have split our coverage into three areas: two-stroke outboard motors, four-stroke outboard motors and inboard Gas or Diesel engines. Click the links for full instructions on using Engine Release to free seized-up marine engines.

Two-stroke outboard motors
Four-stroke outboard boat motors
Inboard Gas marine engines
Diesel marine engines 

Industrial engines

We will be happy to advise on an individual case-by-case basis for industrial engines.

Please contact us with your requirements by clicking here.

Boat motors, such as four-stroke outboard motors, can seize. Engine Release will free them

Boat motors of all types can be rescued from a seized engine by Engine Release.

Regardless of the type of engine and vehicle you intend to work on we have specific instrcutions for your project on our site. Click the links on the left-hand menu to be directed.

Four-stroke outboard motor

This page provides instructions for using Engine Release to free seized four-stroke outboard motors. It works, OR YOUR MONEY BACK. Click here for more about our no-quibble return policy.


Once you have read these instructions, if technical support is required with your project please email us for advice, we will reply ASAP.

Warning: Read safety warnings on the Engine Release container before continuing. Click here to read the safety information online BEFORE using Engine Release on boat motors.

Engine Release will damage paint finishes. A warm water and detergent rinse will neutralize Engine Release.

If you have failed to free up your marine engine previously, even if it's an antique outboard motor, using Mystery Oil, vinegar, water, ATF, diesel fuel, WD40 or others, purchase a large plastic turkey baster and about 24" of clear plastic hose that will tightly push-fit over the end of the baster and still have a small enough outside diameter to pass through your spark plug holes.

It's important to remove all traces of other substances with your baster so they will not dilute the Engine Release when you inject it into your engine.

It’s a good idea not to try and force more hose down the boat motor's spark plug hole than is required to just touch the top of the piston, so you can be sure to get everything.

Pushing more hose into the cylinder than is required will just force the end of the hose to curl up in the air, defeating the purpose of this exercise. You won't find this advice in your Mercury outboard repair manual!

How to use Engine Release to free up your seized FOUR-stroke outboard motor

 Tools of choice:

  • Impact Wrench: electric or pneumatic
  • Sockets, breaker bar/ratchet
  • Large pry bar or screwdriver

To free a seized outboard motor, you need to position it horizontally on a solid work bench or the floor.

To free up your seized four-stroke outboard:

Position the engine horizontally on a solid work bench or on the floor, propeller facing up. Put a few blocks under the prop gear case so the engine cylinders are in a vertical position. The closer the boat motor's cylinders are to vertical, the better the results.

When Engine Release is injected into the cylinder bore/bores, it will flow freely around the boat motor's pistons, not leaving any dry areas. Your boat repair manual won't tell you this.

Remove engine cover and all spark plugs. If corroded or seized, a few drops of Engine Release on the plug's threads will make frozen plugs easy to remove. (Let it soak in for 15-20 minutes.)

A seized outboard motor can be freed using Engine Release. Inject it into the cylinders every day and leave to soak in for a week.

Twice a day, morning and evening, using your Engine Release injector bottle, wet each cylinder with a half oz of Engine Release. Three or four days of this should do it. Let the Engine Release soak in for a week then proceed to the next step.

Now you require a firm support, like a 2" x 4" or 2" x 6", held in a bench vice or an extremely secure engine stand, to clamp the outboard onto so it can be worked on.

If you think you can secure your outboard motor on your bench or stand, you can work on them where they are, it's your choice.

You need an extremely secure engine stand or mount to clamp your marine engine to before you work on it.

Remove your boat motor's pull start mechanism.

There are three bolts holding it.You should see the starter ratchet ring and crank nut.

This shows a close-up of the starter ratchet ring and crank nut when you have removed the pull starter from your antique outboard motor.

Before you crank your boat motor, cover the spark plug holes with a rag to keep Engine Release from blowing out of the holes.

WARNING: Keep your face away from this area. Do not use battery start for breaking the engine free.

Cover the spark plug holes on your seized marine engine before cranking it.

Put a socket on the boat motor's crank nut and break the engine loose with either an air or an electric powered impact wrench. Don't have one? Rent or borrow it if you have to, it's the best tool for the job!

Hammer blows from the impact wrench set up vibrations in the engine that, with the help of Engine Release, will dislodge oxide crystals from one another, freeing up the engine. Short bursts of the impact (1 or 2 seconds) duration are all that you need.

If you don't have access to an impact wrench or don't want to use one, a socket and breaker bar of your choice will do. Go for ratchet ring or crank nut. (We do not suggest this approach.)

Cover the spark plug holes with a rag before you crank the marine engine to free the corroded cylinders.

When working on an outboard engine repair in a horizontal position, you should still cover the spark plug holes with a rag before you crank the marine engine to free the corroded cylinders.

Once the engine starts to turn STOP! Disregard the next paragraph regarding the valve train.

Even if it refuses to turn, also STOP! Consider following the next paragraph, but the engine may just need more Engine Release and time to free up.

Time to give the boat motor's valve train some attention. Remove all valve covers. Valves that are closed should not have seized, valves that are rocking are the ones that can give you trouble. They can seize by the valve's stem in its guide, if partially opened or partially closed. Put a few drops of Engine Release on the valve's stem using your injector bottle to get between engine valve springs and valve guides.

Now using either a hard rubber mallet (or plastic-coated, no-bounce hammer) give any valve that may be binding in its guide a short firm light blow, just enough to move the valve in its guide.

Now go back to your impact and socket. If engine starts to turn, STOP! Repeat valve-related procedure a second time, only worrying about the valves that are half opened or half closed.

Add a little more Engine Release to each of the boat motor's cylinders. Cover all open spark plug holes with rags so that no Engine Release is blown out the holes when you crank your Engine. WARNING: Keep your face away from this area.

Once the engine is turning nicely, re-install your pull start. You can now crank the engine using either your pull start or battery start if so equipped.

If everything seems to be nice and free, check your spark plugs for a good spark, then re-install them as well as your valve covers and the engine cover. You can now test run your engine!

It's a good time to give the exterior of your engine a wash with warm water and detergent to remove all traces of Engine Release. Engine Release will damage paint finishes.

V-style four-stroke outboards

V style boat motors aren't any more of a challenge than inline models. The only difference is the amount of Engine Release required to free them up. The procedure is the same otherwise.

This photo shows 4 oz of Engine Release doesn't reach the high side if the piston.

These photos for demonstration purposes show you a cylinder bore in a V-style engine. Note 4 oz of Engine Release doesn't reach the top of the piston because the cylinder is inclined photo shows the actual level of the Engine Release as when the engine is installed in the vehicle. A full Engine Release kit is required to flood the cylinder and reach the high side of the piston. If the same engine is loose or on a rotating stand blocking or rotating the engine so that one bank of cylinder bores are vertical to the ground allows you to work on them in a position thats allows the Engine Release to flow evenly around the piston crown requiring much less Engine Release to do the Job. There is no high side that stays dry.

One can of Engine Release is required per cylinder as a minimum to reach the top of the piston with enough Engine Release to wet everything required. There is no other option, because of the cylinder's angle in the engine block.

Flood each of the boat motor's cylinders with Engine Release. Let it soak in for a week, then follow up our step-by-step instructions until your seized marine engine is freed up.

Higher horsepower engines that are on a boat can be leveled out if the boat is on a trailer, by lowering the tongue jack on your trailer. Tilt your outboard up and work on one bank of cylinders at a time. Alternate between banks. Engine Release does not evaporate, so you don't have to worry about your treatment drying out.

Turn your steering so as to position the cylinders in a perfectly vertical position so that when Engine Release is injected into the cylinder bores, it will flow evenly around the piston crowns. This technique can save you removing the engine from your boat.