1972 Merc 650 3 CYL.... No Spark

[timmeraw]

Re: 1972 Merc 650 3 CYL.... No Spark

Yes Sir....top carb float had sunk :-0. Full of fuel. Adjusted the drop settings etc and replaced and put it all back together. Pumped ball and it stayed hard with no fuel leak.

Started cranking but no ignition. Squirted pre-mix into the plug holes and she roared to attention. Had to tap the choke a few times to keep her running but soon it warmed up and started playing with the idle adjustments on carb and motor and cable and got it idling good in a barrel at 11-12k rpm( oh yea...bonus...the tack on the dash is working . It was also pumping really well and stay cool as a cucumber.

Now for the problem..... It will only start cold with pre-mix in the cycls. When warm is fires right up. I am pretty sure I have the timing belt set/install correctly (without the pointer... I set Flywheel to TDC and then point the arrow on the distributor wheel directly to center of flywheel.....does that sound correct?)

 

[Gibbles]

Re: 1972 Merc 650 3 CYL.... No Spark

Glad to hear you got the fuel issue figured out.


For the timing; that sounds close but not quite right

I'll have to get some pictures/scans from the merc manual about how

the dist pully ha a mark that needs to be lined up with a mark on the dist base

then the plastic timing pointer aligned with the belt alignment mark on the flyweel

it would of made much more sense to do it as you mentioned.

And if your missing the stickers on your flywheel, there should be some punched marks for both TDC and the ignment mark on the flywheel...

 

[timmeraw]

Re: 1972 Merc 650 3 CYL.... No Spark

Well the issue is not the sticker which is there, or finding TDC.... problem is that there is no pointer to line up to the belt alignment line. BUT ... I assume if it were there it would line up with it where I have it set using the old fashioned pulley arrow/TDC method.

 

[Gibbles]

Re: 1972 Merc 650 3 CYL.... No Spark

Well the issue is not the sticker which is there, or finding TDC.... problem is that there is no pointer to line up to the belt alignment line. BUT ... I assume if it were there it would line up with it where I have it set using the old fashioned pulley arrow/TDC method.

I'll take a look at mine when I get home, and I assume you are missing the pointer?
I found it for sale a while back, it's handy to have.

The other Issue you may have, if you took off the flyweel to replace the belt, make sure you have it on the same way it was, if not you will need to set the #1 piston to TDC and move the flywheel to match the TDC location for the pointer...

If your gtg there, I'll see about getting a picture to help you figure out where the correct setting.

And here is a timing pointer (where I bought mine)
http://www.marineengine.com/newparts/part_details.php?pnum=MER62397&ptype=&Engine=&Model

 

[timmeraw]

Re: 1972 Merc 650 3 CYL.... No Spark

I removed the flywheel to replace the belt but I used the proper puller and it is keyed so it can only go back on the same position that it came off. I can simulate a pointer if I can just figure out which bolt it is attached to. My old service manual shows a pic where it is over near the starter....then I saw another one where it was attached to the inside bolt of the distributor on the that sided.

In any case I think I know what some of the issue is. This distributor that I got off of the donor 650 was very stiff(almost stuck) when I first removed it. I worked it some and shot some grease into the filler nipple but I gotta tell ya it was still pretty stiff when I put it back on. It is cause a very slow response on the throttle cable return to idle etc. THink I am gonna have to remove distributor and see if I can get it apart to check/clean the bearings etc. Should it be pretty free wheeling between the distributor and and the upper housing??? As in...is there anything else that advances or retarts the spark besides the arm connecting it to the throttle arm? It certainly seems that I can manual turn it some to increase/decrease the spark/rpms.

 

[Gibbles]

Re: 1972 Merc 650 3 CYL.... No Spark

I hope this helps

(1974 merc 650 3cyl)

Pully lined up

Lined up with timing pointer

Lined up using straight edge

I know 1973-75 are the same, but I'm not sure about a 1972, but I think the 3cyl models are mostly the same...

And I have two of these engines, a 1974 and a 1975 if it helps (they are the same in every way)

 

[Gibbles]

Re: 1972 Merc 650 3 CYL.... No Spark

Also, the engine pictured had a very stiff dist also
that engine had been sitting in a barn since the late 70's

When I had the flywheel off to change the belt I pulled the pully off and ran some seafoam down through it and worked it around
finally started to free up and works pretty good now with fresh grease

 

[timmeraw]

Re: 1972 Merc 650 3 CYL.... No Spark

Thanks Gibbles... those pics help a lot. This should help me determine if I have it lined up at the right initial spot. Here is a picture of my motor with the little cast marks lined up on the wheel and housing. Looking straight on the mounting post where the pointer should be...it looks like belt alignment line is straight ahead. It's hard to compare though without the pointer.




Ok so assuming I am at least really close on the belt/distributor alignment......now what is the issue with the hard start?

It will not kick without squirting premix in the cyls. Doesn't seem to be able to suck fuel thru the carbs and into the cyl's.
Could it be a reed issue?

 

[Gibbles]

Re: 1972 Merc 650 3 CYL.... No Spark

I would think a reed issue would cause issues with idle/stuttering, popping through carbs, ect.

It could be as simple as mixture or timing

Usually a richer setting will help it start up.

Also when starting, are you testing with muffs or in the water?
And if in the water, how deep?

I had some minor starting issues when cold on my engine, but I pushed the timing back just a little until I was happy with the idle, then took it to the lake for the final tune, so far is fires right up.

Timing is easy to set on these engines, just set the stop back on the left side (near dist) and advance for power on the right.

Setting my timing back helped starting, to far back and it would hesitate when moving throttle forward

Also I assume your using the warm up lever + choke to get it started?

Also look at plugs, and battery condition

Also the plugs I'm running are NGK BUHW

Try starting it using a starter rope, at the top of your flywheel there should be little "hooks" you can knot a rope on one end and put it in the catch, then wrap around the flywheel, give it a good tug
if it fires right up, your battery may not have enough power when cold to crank the engine and get the ign to fire.

 

[Gibbles]

Re: 1972 Merc 650 3 CYL.... No Spark

And you do look very close, if your off it may be by only one tooth.

Check out that link I gave ya, the timing pointer is very handy to have.

 

[timmeraw]

Re: 1972 Merc 650 3 CYL.... No Spark

Ok...played with it a bit this morning. It will start cold (after say 5 or 6 tries) when I make sure I pump the bulb rock hard and then some...make sure the warm up throttle is all the way open....use the choke of course. When it kicks it ROARS(because the idle lever is so far advanced) and I gotta quickly bring it back to less than a third....tapping the choke once or twice if necessary to keep it from dying if I pulled back the warm up throttle too far). I was re-reading my original service manual instructions about initially turning back the idle screws one full turn after cleaning the carbs. BUT....I found with this motor...that is not enough...I turned them to 1 3/4 and it started. Hmmmm I just had a revelation... I realized that I r&r'd the carbs but with all the no-spark issues, I have forgotten to do check/clean/repair the fuel pump....could be the root of my issues actually.

In any case to answer your questions. I am running in a barrel with water about 8 inches above the impeller(pumping like a champ).

When you talk about adjusting the timing and say "set the stop back on the left side (near dist) " are you referring to the pickup?

I may be off a tooth on timing belt(will pop the fw cover off and the distributor wheel cap and double check that I have that arrow pointing directly to crank at TDC).

Have not changed the original plugs that were in the motor when I got it and will change them.....Battery is not the greatest but certainly cranking faster than I could ever do with a rope.

Stay tuned(no pun intended) and I will get back to you soon.

****UPDATE**** 1 hour later.

Checked cleaned the fuel pump and strainer. Adjusted the pickup a bit. She is idling pretty darn good now as seen in this little video. It is idling in the barrel at right about 1000 rpm and when I threw it into gear it dropped to about 800 with no stall. Should be good until I get it on the water. I have read and noticed first hand that these motors sure need the fresh air which is why I have the front cover off here.

Thanks for your ongoing help.

Now I can concentrate on getting the new floor in and taking her for a spin

Tim

 

[Gibbles]

Re: 1972 Merc 650 3 CYL.... No Spark

yeah start with new plugs, the ones I posted work very well IMO

use a straight edge as noted in the picture above
pretty much line it up with the hole for holding the timing pointer

I'll have to get a picture of the timing adjustments to make more sense.

 

[Gibbles]

Re: 1972 Merc 650 3 CYL.... No Spark

Also it may sound silly, but if the battery is kinda dead it will turn the engine but may not have enough juice to give the plug enough spark to get it started while cranking.

Ran into this on another outboard, finally while at the lake about to row the boat to the dock, park the truck, and swap batteries I got the bright idea to try a rope... it fired right up! :facepalm:

 

[Gibbles]

Re: 1972 Merc 650 3 CYL.... No Spark

Just saw your update; good to hear!

 

[timmeraw]

Re: 1972 Merc 650 3 CYL.... No Spark

OK I will definately charge the battery (as soon as my charger dries out it was in the boat under the leaking tarp after having a brutal few days of driving rain and 2-3 inches of wet snow night before last.

I understand the theory of it needing a good battery with good connections but the thing is that once it is warm....one tap on the key and she fires right up so I think it is just like an old fashioned well with a hand pump that needed to be primed with water to get it working... and like the water pump in this motor....if I start it back up within say a minute or two it starts peeing right away...if I leave it long enough for the water to run back out it loses its prime and it takes about 15 seconds to start pumping again.

THnaks as always.
Tim

 

[Gibbles]

Re: 1972 Merc 650 3 CYL.... No Spark

lol yeah... the boat I mentioned was the same way
once warmed up no issues, but that was in part because the engine was charging the battery while running, so after it was warmed up, the battery had a bit of a charge.
+the engine being warmed up and primed

 

[timmeraw]

Re: 1972 Merc 650 3 CYL.... No Spark

Just when you thought I was finished with issues.....are we ever? Now I am having a couple little things going on.

1) The butterfly's are periodically getting stuck closed when I activate the choke solenoid. Of course this is when I am trying to start it cold and only realize it when it starts and then of course chokes itself out. I don't really see a way to adjust or see anything in the throat that the flaps would be binding on.
Lightbulb!! I recall when I first started tearing this motor down the choke plunger was really stuck up into the solenoid. I pulled it out and cleaned what I thought was the majority of the goop from the plunger but maybe not enough up inside the tube. Gonna pull it again and really clean it.....what about dielectric grease too...that won't interfere with the electrical function will it?

2) After starting with warm up lever and returning it to full down...the throttle and/or spark advance/distributor is not returning all the way to slowest idle(set at around 1000 rpm). Still think it is the stiff distributor housing grease. I'll figure this one out I'm sure with some more tinkering.

 

[Gibbles]

Re: 1972 Merc 650 3 CYL.... No Spark

I used white grease in mine
there is no electrical connection to worry about in there, it's magnetic baby!

 

[Gibbles]

Re: 1972 Merc 650 3 CYL.... No Spark

Here is a basic decription on how to adjust timing

 

[timmeraw]

Re: 1972 Merc 650 3 CYL.... No Spark

Awesome...thanks Gibbles...for all the support from a fellow 'strangy 650 -3" in so many ways. I did use those two stops to get it ticking well manually...I think it is the gummed up distributor that is not allowing it to seat back down....I'll get that solved.

Still gotta figure out how to link-sync with a timing light without the pointer, but for now its time to move on to getting the floor glassed in and finish up the boat. Then I can move on to my two new babies(see my other post here on Fiberglassics: http://www.fiberglassics.com/glassi...9948-two-new-white-mercs-this-week.html#59948

I do like the challenge of waking the dead Mercs much more than the boat restore stuff. That said I did manage to muscle in a replacement teleflex steering on the boat with the 650 tonight before dark.