Merc 200 20hp Lower Unit Re-assembly problem.

[Mac uk]

I have two lower units off Merc 20hp's. The case numbers are 1627 6006 & 1627 4404.

Q. What if any is the difference in the case numbers.

Q. Im having trouble seeting the forward gear in the case.

Is there a difference in the bore sizes used in the cases, or should they be totaly interchangable.

 

[carholme]

Re: Merc 200 20hp Lower Unit Re-assembly problem.

Mac;

What are the s/ns of the two engines?

Don't understand what you mean by "having trouble seating the fwd gear in the case".

In the gearcase in which you are trying to install the forward gear, do you have the engine driveshaft removed?


Gerry

 

[Mac uk]

Re: Merc 200 20hp Lower Unit Re-assembly problem.

Its a long one , but stay with me. I had a Merc 20 1973, but the gear casing got cracked & suffered water ingression. I stripped it for the parts.The gears, prop shaft, dog clutch & pinion gear cleaned up ok, but the bearings & bearing carrier & case were naffed. Ive since got hold of another unit (1627 6006) Stripped it apart (Cause the drive shaft was squared, naffed) at the spline top, I managed to salvage the gears & bearing carrier, althought its not of the 3303 type. its narrower at the top, so the cover nut goes round the carrier top as well as on top of it (bearing carrier 72696 is the number on it). I also got hold a anther case (1627 4404) and its drive shaft. AND another unit I stripped apart, & salvaged the bearings & a bearing carrier 3303 and cover nut, but this unit was an early model with the reverse shift action. Got that so far, im having to think.

My problem is ive assembled the shift cam & shaft in the 6006 case, put the baerings from the early unit onto my 1973 gears, and using the drive shaft & bearing carrier as a guide, tried to put the foarward gaer into the 6006 case, but the forward gear on its bearing, wont go all the way down & sit on the bored lip. there's no drive shaft in to stop it, question ?, is there a problem of the bearing being the wrong one (size) for that case or am I just not hitting it hard enought

 

[carholme]

Re: Merc 200 20hp Lower Unit Re-assembly problem.

Mac;

As the bearing carriers and gear case are all attributed to engine s/ns for the US/Can/Aust/Belgium, etc., I am finding it a bit difficult to build a chart for interchange of the components.

The '73 20hp uses two different carriers 72694T1 and 33402T4 for different s/n engines and from those engine s/ns you would decide which gear casings were interchangeable using the serial number groups as per this link:

http://www.crowleymarine.com/mercury-outboard/parts/464_160.cfm

Without engine s/ns for applicability, I find it a bit difficult.

Gerry

 

[ONERCBOATER]

Re: Merc 200 20hp Lower Unit Re-assembly problem.

Mac uk does that mean your in UK?
just trying to figure out where you are for logistics purposes.

Sean

 

[Mac uk]

Re: Merc 200 20hp Lower Unit Re-assembly problem.

Gerry;

I know, all these parts, I know where they go but do they go together.

Sorry, the only s/n I have is the original engine s/n 03668667 from which I salvaged the forward, reverse & pinion gears, Dog clutch bits and prop shaft. I l;ost the bearing carrier in dissasembly & the case was cracked anyway.

Ill'e make a proper inventry of the parts I salvaged, their part numbers if any and from which LU they came from.

I understand 4404 was superseeded by the 6006, I think, so when did they stop using the 4404 stamp on the cases.

Sean;
Yes im in the UK, the wonderfull green land (green cuase it never stop blumin raining) could do with some of that Arizona sun about now.

 

[carholme]

Re: Merc 200 20hp Lower Unit Re-assembly problem.

Mac;

What part of the UK? I lived in SE London for about 10 years in the 70s.

I cannot find anything about the 4404 case.

Gerry