Every time the boat is used in salt water a small amount of salt builds up on the water galleries. Over time the amount of salt increases. Even with flushing the motor you don’t remove all of the salt. Eventually you will need to have the powerhead gaskets replaced.
What do they do and how much?
When a shop carries out a gasket job, it involves removing the Powerhead or the motor part of the outboard. The shop will clean and surface the Powerhead base gasket area. (This is where the motor bolts to the midsection of the outboard.) It’s a good time while the powerhead is off, to replace the bottom crankshaft seals.
Depending on the manufacturer of the outboard, the exhaust or side plates will be removed and the water galleries will be cleaned and inspected and new gaskets fitted. The heads will also be removed, cylinder block and head water galleries will be cleaned, and water deflectors or restrictors in the water galleries will be inspected or replaced at this time. The thermostats are normally replaced and the heads are usually surfaced before refitting.
Almost all of the gasket jobs I have done have required the use of an air or battery drill to literally drill out the salt build up in the water galleries. I have seen some engines with salt build up so bad that it has actually blown the side of the block out due to the pressure of salt building up. These motors were unable to be fixed and the customer had to purchase a new engine. It is a very important part of servicing, so find out when your motor last had the gaskets done before its too late…
It is a costly job, and it pays to book the boat into the shop during winter time. It’s best for the shops because they are quiet. It helps them out by giving them the work, and most shops are usually very busy in summer and might struggle to fit you in. Sometimes certain shops run winter specials…. So with a big job like gaskets, it will save you quite a lot of money if you can get the winter special.
If you’re not sure if you have had the gaskets done, or if your engine is coming up to about 5 years old, ask your dealer when they recommend doing the gaskets. Get them sorted before it’s too late and costs you a lot of money.