I need expert advice (not the manufacturers)

Hi,
I'm new to this forum and am impressed at the knowledge I have read herein.

I have a 1969 (I think) Mercury/kiekhaefer 500 (50hp in-line 4)

In the manual (yes, came with the motor) it tells me to use 50:1 if I use the "Mercury formula 2 oil" (Witch I cannot find anywhere) and If not available, to use an approved oil at 20:1!!!
I assumed by "approved" they mean TCW-3 rating.
I have run 3 tanks of gas at 20:1 (1 litre of Tech 2000 for 20 litres of gas)
and have experienced some problems;

When wide open, it seems to run great... not too smokey, sounds good, runs full speed (about 30-35mph on a 1969 14 foot fiberglass Vaguard)

But it won't start without the choke (unless it's hot already)
If I put it in gear (reverse or forward) at idle speed, it will go but if I give any gas, it stalls.

I find that I need to use the slow idle speed lever to boost the rpm's THEN get the boat moving in gear before I can give it any throttle.

I pulled the old plugs when this first started to happen and found that 2 plugs were decidedly carbon'd up (While the other two seemed "clean")
unfortunately I failed to note if the two fouled plugs were working o the same carb.
There old plugs were 20 years old, so I put in new ones and will take them out next weekend to check if the condition is persisting unless one of you experts tells me it's something else. (It has only been maybe 3 hours of boating on the new plugs... stalling problem still exists)

Is this just Mercury trying to get people to use "their" oil or should I continue to run that thick 20:1?
All the oil-mix advice I have read on this site has stated 50:1 for this vintage... That's what the book says (as long as I use that oil I can't find)
Any and all advice is greatly appreciated!
I am willing to e-mail out the scanned original manual (if anyone needs it)

Thanks in advance,
Clint Gerus

Re: I need expert advice (not the manufacturers)

mix at 50:1 some people i know in the rental bussiness mix a LITTLE heavier and have longer bearing life. excessive oil, will burn incomplete and cause carbon troubles, fouling and dirtier exhaust in the water. i'd do a decarb and clean it out a bit. it may need to get a few tanks of fresh fuel in it to smarten up a bit. i've got my idle speed set low so it will troll good on my 66 50hp and it reacts the same way till good and warm. never stalled when the previous owner had it set way to fast. might just need the carbs tinkered with a bit, you never know what the past owners have played with.
http://forums.iboats.com/showthread.php?t=158076

Re: I need expert advice (not the manufacturers)

Wow!

That's some quick advice! (got it faster than It took to type the question)

I worry that a leaner mix (50:1) will burn the motor.
If I have heard anything consistently, it's;
"if you don't know, go rich... it might gum things up, but it won't ruin your motor"

I trust your advice (seems to jive with the other related infor I have read on this site)
I just wonder if it might be worth running progressively leaner tanks;
30:1, then 40:1... and listen for any "pinging"?

I thought about moving up to the Castrol super oil (a little more expensive but it's available in a 4 litre jug at Wallmart) It's still 1/2 the price of the "Mercury" oil I can get.
You know at 20:1, It takes $12 worth of the fancy Mercury oil for about $23 worth of gas!!! (today's prices) 5 gallons mixed = $40 = 1 hour on the water...
Ouch!

I find that trolling is not well liked by the motor, it seems to like 1/2 trottle or full only. I assume that's "conditioning" over the last 25 years of use.

This rig (boat & motor) are in great shape considering they have many hundreds of hours on them, I want to continue the "respect" they've enjoyed over the years. It would be a shame to "break up the team" and wreck the motor.

Thanks a million for the advice...
it's nice to get a straight answer!
Clint Gerus

Re: I need expert advice (not the manufacturers)

when you have the plugs out, take a look in the cylinders for carbon. carboned up rings are what will be deadly to you if a ring breaks off. read the link in my other post for decarb, that can make a big difference for cleaning things out. use good quality oil, always with TCW-3. 400 ml to 20 litres is correct, i always mix in a jerry can and add as needed. fuel stabilzer helps a lot as when gas is mixed it ages quick. don't worry about gradually reducing oil, just goto the right mix. when they talk about rich/lean thats your fuel mixture on carbs. mine was rough running to start, a few tanks of new clean gas and it ran better. a midgrade fuel on the older motors also helps

Re: I need expert advice (not the manufacturers)

Re: I need expert advice (not the manufacturers)

there is no reason what so ever to run that motor at such a heavy oil mixture,50.1 is just fine.ive owned mercs for 30 years or so until my last or should i say current motor.my last motor was a 1964 65 hp merc and was run for years at 50.1.its still running today!

Re: I need expert advice (not the manufacturers)

50:1 is just fine , any TCW-3 oil . running a 1962 Kieckhaefer 45 hp 4 cilinder.

Re: I need expert advice (not the manufacturers)

just to add a little you were reving the engine up a little then putting it in gear? If so that is not a good thing on the lower unit my friend. Especially if the unit is clunking when going into gear, if it is clunking try setting the idle a little higher till it stops stalling and it doesnt clunk into gear good luck

Re: I need expert advice (not the manufacturers)

Clint...I would like to see the section of the '69 Merc. manual that deals with changing the throttle/shifter cables if possible.

Re: I need expert advice (not the manufacturers)



Cool looking motor; here's the 69'

Your motor reminds me of my 65' evinrude litetwin 4hp