50HP Merc problem

Slaphead · 25 March 2006, 15:11

I have just taken possession of a circa 1970's blueband Mercury 50hp hand-start engine.It has 500 on the cowling and has 'Thunderbolt' ignition.It has been unused for about a year but started on the 4th or 5th pull.

Two problems:-

1. Its not pumping out any water through the tell tale.Does that mean the impeller is stuffed and if so is it a hard job to change?

2. The engine will not turn to the left or right without me pulling or pushing at it despite me pumping copious amounts of lithium grease via the grease nipple on the yoke. The new grease will come out of the bottom but not out of the top of the steering yoke. The old grease is like clay. Would some gentle heat on the area help to melt the old stuff and free it up or am I looking at a strip-down job?

Paul F · 25 March 2006, 16:39

A real golden oldie.
Impeller may be stuffed or there may be a build up of old salt around power head or tale tale hole? Check impeller and if you can put some air onto copper pipe (inside lower unit once gear box removed)going up to power head.

As for swivel bracket dont put heat on it there may be plastic/ rubber bushes or washers in there. Might be a strip if you cant free it up
Paul

Slaphead · 25 March 2006, 19:58

The engine came on a boat together with a 9.8hp Merc same vintage I bought on e bay.The 9.8 started on the 4th pull and there is no problem with it. The chap told me it was last used in the freshwater part of the Thames.

I don't know what to do about the steering aspect. Is it going to be viable to get a marine mechanic to strip the thing down to free it up or to just get another newer engine. I'm loathed to get rid of something which clearly works okay apart from impeller problems. The tell tale hole is clear and I was able to suck up fresh water from where the pipe goes into the head.

Is there any way I can get releasing agent into the yoke that supports the steering mechanism?

Paul F · 25 March 2006, 20:25

Due to amount of grease in there nothing will get pass to soak as a free agent.
Certainly not worth taking it to shop to be done. Do it yourself if you can
Paul

David G · 25 March 2006, 20:42

Is it all disconnected from the steering system?

If not it is more than likely the steering cable that is seized not the motor yoke...

Just my twopenneth!

Regards,

Orve

Slaphead · 25 March 2006, 20:56

No the steering system is disconnected and the cable steering bar runs freely.
The problem lies in the motor yoke.Is it a power head off job and if so what is the potential cost? Don't want to throw good money after bad.

jyasaki · 25 March 2006, 22:40

You're talking about the bearings that the motor pivots around on while turning? I would doubt that there are plastic pieces in there, but I could be wrong. Shouldn't be all that big a deal to take it apart. Should not have to disassemble the motor to get to this. [edit: You will have to support the motor while you work on this.]

The impeller should not be a big job, either (if you don't know when it was last replaced, or it has been more than a couple of years, it would be prudent to do it anyway.) A few bolts, remove the lower unit, and have at the impeller cover.

jky

Nos4r2 · 26 March 2006, 10:23

Change the impeller anyway-if it still doesn't pump water you can backflush these engines through the telltale with a hosepipe to help clear any blockages.

There's no plastic parts in the steering yoke. The chances are though that the bottom bush is more worn than the top hence the grease only coming out of there which is usual on blueband 50's.

From memory I think it IS a powerhead off job to remove the yoke as it makes it an awful lot easier to do anything-but it's really easy on these motors as long as nothing's siezed- I've done the whole strip/rebuild from start to finish on one of these in under 4 hours.

Slaphead · 26 March 2006, 19:36

Thanks for that chaps.I'll take it to a local marine mechanic here in Bangor and see if I can get a price off him.I think at least I can get the impeller done and if it is going to be uneconomical for me to get the thing fixed fully, at least if it running ok it might make a good engine for someone in the know who can sort it out and I can recoup some of the costs. Hand start 40 or 50hp's don't seem to be that expensive in comparison to all singing all dancing ELPTO,TLDI etc,etc.

Slaphead · 03 April 2006, 21:08

Got my engine back today from the mechanic.He turned the engine upside down and put loads of heat on the steering yoke to melt the old stuff inside and was able to eventually loosen it.Apparently grease doesn't get to the top seal hence the problem of seizing if left for a season.

New impeller also fitted(brass inner).Old one wasn't too bad but the problem here was a build up of crud at the elbow joint where it came out of the power head. Engine serviced, compression excellent on all cylinders and all for £100... happy days!

djbk · 11 July 2006, 20:16

you need to take apart your gear box and rebuild the water pump, is real easy just undo the bolts and shift shaft and the pull it out, check impellor key!!!
the key is what drives the impellor!!

for the steering disconnect is and pull it out off its slot and clean inside probably is clogged with dirt, then grease it back up and should be ok

djbk