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1984 35 hp rebuild - reed block / main bearing question

E

EdBass

New member
Hi all,
I'm rebuilding a 1984 35 hp engine with serial number 06491413. I bought a used powerhead block that was empty of parts and I'm building it with new parts before swapping it with my existing old powerhead so I don't have a visual reference of these parts outside of the diagrams. This is my first marine engine rebuild but I have experience building automotive and other 2 stroke engines. In the diagrams, it lists the reed block as a "main bearing assembly" but from what I can tell, there is no bearing nor needle bearings that go between the crank and the reed block. Does the crank journal float in the center of this reed block but never touch it? I find it interesting that there would be a gap there because I see that as a gap where fuel/oil could go between the cylinders and bypass the closed reeds on that side.

Thanks,
Ed
 
Here is a picture. It looks gnarly if those ridges would actually clamp onto the crank journal. But maybe it's designed that way so oil reaches it (and maybe that's why there's a pin hole in the back)?
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Those ridges are "labyrinth" seals to seal one cylinder from the other if they have sharp edges then they are OK and they don't contact the crankshaft.
 
How far have you made with your engine?
I am doing the same thing with a 97 4 cyl. Were you able to install the pistons before the crank? Then install the rod bearings?
My manual shows to install the crank with the pistons with the ring compressors.
Also are your rod caps machined were they meet the rod or are they the fractured type?
 
We just got the new pistons in, I am 3D printing a piston rod tool that holds the needle bearings in place while the wrist pin is inserted. I plan on following the manual and installing the pistons to rods, then rods to crank before dropping the whole shebang in the block.

I still have to buy the ring compressors.

My rods are end caps are milled.

I bought .030 over pistons and I’m going to take the block to my machine shop to have it bored and honed. I want to assemble the pistons on the rods first because I give them the pistons so they can fit each piston to the corresponding cylinder and test the clearance. Putting the rods on there gives them a “handle” to work with.
 

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I use a wrist pin polished down to hold greased needles in place while pushing in the wrist pin.----Should not need ring compressors with that style of rod / bolt set-up----That is my opinion.
 
Who are you buying parts from? I am looking for part # 854913 a exhaust baffle gasket. Can't seen to find one and my sierra hook up isn't around...
I was surprised to see my rod caps fractured cut. I never thought it was done around 97 or so. I am sure it is cheaper that way.
Since we are both this far into our engines I wonder would there be any gains to balance and lighten the rotating parts.
On my engine no drilling on the counterweights on the crank.
But it maybe weighs 20 lbs. Prob not any need to do that.
However the engine turns around 5K rpms.
If you don't mind to ask your machine shop to see what they think.

 
racerone said:
I use a wrist pin polished down to hold greased needles in place while pushing in the wrist pin.----Should not need ring compressors with that style of rod / bolt set-up----That is my opinion.
Click to expand...
What do you think is the best way to install pistons? My engine has a camfered cut in the liner. I was going to use a screwdriver and nudge the rings in. However, it ins't a 4 stroke engine with a head on it. Every thing is reversed.
What do you think?
 
eclipseguy said:
Who are you buying parts from? I am looking for part # 854913 a exhaust baffle gasket. Can't seen to find one and my sierra hook up isn't around...
I was surprised to see my rod caps fractured cut. I never thought it was done around 97 or so. I am sure it is cheaper that way.
Since we are both this far into our engines I wonder would there be any gains to balance and lighten the rotating parts.
On my engine no drilling on the counterweights on the crank.
But it maybe weighs 20 lbs. Prob not any need to do that.
However the engine turns around 5K rpms.
If you don't mind to ask your machine shop to see what they think.
Click to expand...
Mostly getting parts from this website (marineengine) and ebay. I had to order an entire gasket kit to get gaskets because I couldn't find them individually.

My marine repair shop said they get most gains from grinding the intake and exhaust ports on the sleeves to match the holes in the block. I don't plan on porting it. I can ask my machine shop about the crank, they definitely lighten cranks because people have them do work on their race engines.
 
Hello I have a 1984 35 hp mercury I can’t get it to start at all!! Even with dumping mixed fuel in the carb while cranking and even tried starting fluid but only couple short bursts. I have spark on both plugs good spark brand new battery I have 137psi and 134psi on compression brand new fuel pump kit new float and adjusted taken apart twice and cleaned thoroughly. Even while dumping fuel in the face of carb while cranking the spark plugs are still dry. Is this reed failure?
 
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