Mercury 82 2.4 200 Power Head Rebuild

[Steve200]

Howdie,

I'me rebuilding my old 82 chrome bore 200. I've got a rebuild kit for it from TSM, and Bob's Race Reeds and stacks (I love the sound) coming soon.

Looking for some advice on the rebuild,
I'm going to cut the heads, aiming for 140-150psi. How much should come off it ?

The carby primary jet grub screws are all jammed in place the metal gives way trying to turn them. I can either drill them out or get new carbs. They are WH-31's. Is there something else I could use for better performance or should I stick with them?

Also the powerhead studs are corroded so badly that I think I will need to drill them at 90 degrees into the lower exhaust / separation plate. Is that the best way to go ?
Cheers
Steve

[W2F a V-King]

If you search this site, there are guys that faced a similar issue as your situation, and have threads with their efforts and results. Saltwater motors can present challenges.

Good thing is if I remember correctly, that XK in the casting stamp is of the newer alloy. I know early Merc V6 motors had some corrosion issues with the first years mainly saltwater motors corroding. Not sure when they changed the alloy recipe.

Tons of carbs available. No worries there.

Think I would take everything apart before I started buying to many parts...never know whats inside, unless you've had it since new. jmo..

You could likely find a drop on 2.5 200 and be ahead in all respects...

[Steve200]

Hey V-King, thanks for your reply.

Yeah read a lot about the corrosion issue and my conclusion is to drill 90 degrees into the exhaust plate to chop the bolt. The local boat wreckers have a plate if I need one, but from what I have read you can reuse the old plate even after its been drilled. Just thought I'de double check, because everyone has an opinion and someone might say .... hell no, don't do it that way!

The heads are off and the bore looks very good from the top, its round almost perfect (1 pinprick sized pit). The water jackets look fine (its been fresh water for the last 7 years).

I can't find a 2.5 power head down under in Australia for under $4K. If I can rebuild my 2.4 for $2K I'll have a new powerhead ... better than new.

[W2F a V-King]

Well that's good to hear about the condition of the block. Those small pits are OK....they hold oil. If they were an issue you would have had problems long ago.

Wonder what shipping would be from here to there for a power head?

Not sure what your power needs are but the difference between the 82 200 and a 96 up 2.5 200 is worth investigating.

[Steve200]

Yeah thought about a 2.5, but its still going to cost more to put a second hand 2.5 power head on than to rebuild mine. My neighbour has been building and racing boats for 50 years (and his father before him too) so I have plenty of support on the rebuild .. I'm actually really looking forward to the rebuild.

The other thing about the 1982 2.4 is that it only weights 366lbs which suits my 14 Foot boat nicely ! I think its the lightest 200hp outboard ever made.

How about the heads on those old 2.4's ? Its a 2 peice head, I can't find any info about shaving those heads and how much I should be looking to take off ? Anyone ?

Cheers
Steve

[90 5.0]

32cc will give you about 140-145, 31cc will be 150-155 on a 2.4 200

[Steve200]

32cc will give you about 140-145, 31cc will be 150-155 on a 2.4 200

Great thanks for the info, 32cc will do the job then.