See full version: How to Install Outboard Motor Head Gaskets
Exhaust smoke leaking from your outboard's top cowling is never a good sign. It usually means that you need to install a new head gasket on your outboard motor to prevent exhaust gases from escaping from between the cylinder block and the powerhead block. The procedure is straightforward and, as long as the gasket is sealed and the cylinder block is properly tightened to the correct torque, it should alleviate the problem.
Remove the cylinder block bolts with an adjustable wrench. Lift the cylinder block from the powerhead. Remove any gasket sealing compound residue from the surface of the mating surfaces of the cylinder block and powerhead block, using a plastic scraper.
Spread a thin layer of gasket sealing compound on the top and bottom sides of the new cylinder block gasket and position the gasket on the cylinder block, using the alignment pins on the cylinder block to position the gasket.
If the inspection does not reveal any major issues, since the heads are off anyway, might want to consider having a valve job if that has not been done before on a 20 year old motor.
Hopefully, there is no damage to the cylinder walls. here
So, lesson for the day is do not run your boat back to the dock once the impeller craps out. [links]
Re: Head gasket replacement cost?
Re: Head gasket replacement cost? more
Blew the impeller and ended up running her hot back to the dock. Unsurprisingly the two front cylinders are only pushing around 50psi so I likely blew both gaskets (knock on wood that no warping occurred.)
You can take the cylinder head bolts to your local hardware store to find the bolt size and thread pitch. With this measurement you can purchase a tap of the same measurement. Use the tap on the cylinder head bolt holes to clean any dirt that has settled along the threads. here
Periodically check the readings on the instrument cluster and also step out to the engine bay to look for any leaks or smoke. Sometimes the new seals, especially head gaskets and exhaust manifold seals, may give off some steam or smoke. more
The service manual will list special tools required for repairs and will specify which components to remove while performing the repairs. It may be necessary to look over the procedures a couple of times before beginning. Get familiar with the work you are going to perform before starting to work on your car’s engine. here
Step 1: Spray the cylinder head gasket with sealant. If applicable, spray both sides of the cylinder head gasket with the sealer before laying it onto the clean engine block. Otherwise, lay the bare gasket onto the clean engine block.
On OHV(overhead valve) applications, you may not have to tamper with the timing components. On an OHC(overhead camshaft, single or multiple) application, the timing components must be disassembled to remove the cylinder head. Follow the directions in the service manual for proper assembly. here
Sometimes, a blown head gasket allows coolant and oil to mix which is noticeable by the presence of mayonnaise-like residue on the oil cap. Finally, a broken or blown head gasket can result in increased oil consumption and damage to the exhaust systems, catalytic, and cylinder heads.
Also, the physical damage to the head gasket allows the oil and the coolant to mix and enter the cylinders, which can be fatal for the engine itself if not diagnosed early.
As we already mentioned, the head gasket is a simple and cheap part. The cost of brand-new head gaskets rarely goes over $100, and most are well below that. However, the head gasket repair job can be very expensive because of the labor involved. [links]
The first step is to remove the intake system and all hoses and wires before you get to the cylinder head or heads. Removing the intake system should be done carefully since you don't want anything to be damaged. After you fully remove the intake manifold, hoses, wires, and fuel lines, you can approach the cylinder heads. In order to remove cylinder heads properly, always consult a shop manual for your specific car/engine type. Different engines require different procedures and if you want to preserve the cylinder heads, bolts, and other components, be sure to follow the instructions. more
The second sign is the possible overheating of the engine because the exhaust gasses are forced into the cooling system. Also, with a blown head gasket, coolant can enter the combustion chambers causing possible hydro lock and extensive engine damage. This only happens if a large amount of coolant enters the engine. [links]