anything i should do while powerhead is off?

[1979checkmate]

Hi everyone!

I currently have the powerhead off of my 1979 merc 115 inline. I am in the process of painting the motor and powerhead removal is the only way to get teh lower cowling piece off. I also wanted to replace the gasket between the driveshaft housing and powerhead as i have been fighting low water pressure at idle speeds for a few years, and this is about the only avenue i have yet to explore. Anywho..anything i should go ahead and do while the powerhead is off and everything is easily accessible. I replaced the stator, trigger, rectifier, switchboxes and spark plugs in the past few years as well as rebuilt and synced the carburetors. anything i have missed? Is it possible to remove and clean the reedblocks or is it a moot point?

Thanks!
Alex

 

[racerone]

Re: anything i should do while powerhead is off?

Reed blocks are internal and not easy to get to.---Best to replace the lower crankshaft bearing and the 2 seals found there.

 

[wired247]

Re: anything i should do while powerhead is off?

Reed blocks on those things have got to be the worst design ever. Looks like the French designed them. You'd have to strip the motor down to the bare block to get to the crank and even then there are no replacement reed blocks available even though they are a wear item. Reeds you can change. That has nothing to do with your water pressure at idle. Just assuming you changed the impeller? Inside the exhaust chest is another water passage that is a bad design that fails occasionally. Pick up a full gasket set and have at it.

 

[Chris1956]

Re: anything i should do while powerhead is off?

Reed valves hardly ever go bad. Best to leave them alone. If compression is good, leave the block alone. Inspect the water tube, where it is installed into the exhaust extension. They sometimes get crushed, although usually by salt. Do you have water leaking into the cylinders? Hopefully not, but if so, this is the time to replace the gaskets.

 

[1979checkmate]

Re: anything i should do while powerhead is off?

thanks everyone. A little more info. No water gets into the cylinders, and motor runs fantastic. Water pressure is lower than i would like at idle but the motor has never overheated and the water pressure is very good at speeds above idle. I figured getting to the reeds would be difficult and not worth it.

 

[wired247]

Re: anything i should do while powerhead is off?

What is your water pressure at idle? Keep in mind those things have no thermostats so there really isnt anything to make it build pressure

 

[racerone]

Re: anything i should do while powerhead is off?

The inline 6 needs a new impeller every 2 years.

 

[bgc]

Re: anything i should do while powerhead is off?

I would replace the crank seals and bearings while you have it off.
A couple of the guys on JohnsOldMercurys have the program for printing the Mercury "OK" stickers.

 

[1979checkmate]

Re: anything i should do while powerhead is off?

thanks, ill look into the crank bearings and seals. I inspect the impeller every year and replace regardless every 3. The motor sees very little use. This year i was out of town alot and would be surprised if it saw 10 hours use.