Can't adjust timing, Timer base repalcement?

[FillupD]

I have a 73 50hp motor I have been working on and am unable to get it to rev high enough to check timing. No matter where i screw the spark advance screw to it will not change the WOT from 2500. I can screw it all the way in or screw it all the way out. No change to motor running. Is the timer base fried?

 

[mikesea]

Re: Can't adjust timing, Timer base repalcement?

have you checked for spark,comp and fuel to both cyl.you problem is not in the spark advance screw.but now that you moved it ,be sure after you get it running right to get timing correct,or you will blow it up

 

[FillupD]

Re: Can't adjust timing, Timer base repalcement?

The motor runs well at idle and under no load but will only rev to 2500 or so on the water. Thats why I moved the spark advance screw around to see if I could get it to rev any better but it didn't matter where it was there was no change in RPM.
If the arm/ring moved a tiny bit with the throttle or the moved as far as it could there was no change. I thought that was how timing was set. It probably should have made a difference in the running if the timing base is moving around.
Thats why I thought it would have been the sensor coil.
Spark good, coil output @ 14,000 Volts, fuel system good. Runs well at WOT but just needs a to run a little faster.

 

[tashasdaddy]

Re: Can't adjust timing, Timer base repalcement?

check you compression. spark and fuel as mentioned. there is a reason we ask this. report back. have you done a link n sinc. it is a step by step procedure, to set spark and carbs to work at same time, together. it is in the manual.

 

[FillupD]

Re: Can't adjust timing, Timer base repalcement?

Compression on both cylinders are good, Spark is >1/2" Fuel is filtered and getting to both carbs OK. I am going to run out and buy a gauge and see if there is 4 lbs. of pressure on pump. Is this figure right? The cam follower is in the center mark of the cam as the manual shows.

 

[tashasdaddy]

Re: Can't adjust timing, Timer base repalcement?

i have no idea if you have a healthy block, good is not a compression reading. there are many others here that, need and want help. they get their motors fixed, because the answer what they are asked.
we are all good guys, that take time out of our lives to help others, for free, no compensation.

 

[FillupD]

Re: Can't adjust timing, Timer base repalcement?

Readings are 130 and 132

 

[Benny1963]

Re: Can't adjust timing, Timer base repalcement?

is the boat slow what rpms are you running now how big your boat is and weight and design all factor in on how fast it will go you need to know what rpm you are running at if all is well on your motor you said it idles fine and runs good at wot then your motor may be putting out all it can , your prop setup or motor height may effect it

 

[Benny1963]

Re: Can't adjust timing, Timer base repalcement?

soory didnt see the part were you said it would only run 2500 on the water
are your throttle plates opening all the way .2500 is very low i can unhook my timer base and pull 3500 or better
good luck some one will come along that may have some answers

 

[tashasdaddy]

Re: Can't adjust timing, Timer base repalcement?

if your carbs and high speed jets, are 100% clean, you have great compression, and spark, fuel delivery, it sure sounds like a linc n sinc problem. the carbs and spark advance not working together. follow the step by step procedure, in the manual, if you mess up a step, you have to go back to the beginning. this also may help, you do not have the fast start feature so ignore that.

http://forums.iboats.com/showthread.php?t=228183

 

[FillupD]

Re: Can't adjust timing, Timer base repalcement?

I checked timing and set it 4 degree below spec and took it out to the lake. It looks like it runs around 19 degree but at 2500 RPM. Thats all it will get up to.

I checked the voltage of both coils and they where 18,000 at around 900-1000 RPM and 12,000 volts at 2500 RPM. Does this sound right? Should the voltage go down with more load? Is it possible the stator output is loosing voltage as the RPM's go up making it a part that needs to be replaced?

I looked in the manual about the link and sync and it says for my location #10 and the mark and the cam follower are in the center, which it is. Is this all there is to this procedure. It seems all it does is line up the cam follower to
the mark. My throttle and chokes linkage is properly adjusted so the open and close the same.

When I push the throttle everything moves as it should. The high speed jets are clean, clean fuel, good spark. All the manual says about linc and sync is to make sure the cam follower is in the middle of the mark. Is there more to this? I think I must be missing something but what?

My manual is a Seloc 1971-1981 Volume 2 Johnson/Evinrude Outboard Tune-Up and Repair Manual 2.0 HP thru 60HP.
Is this manual too old to properly go through the linking of carbs to spark? I don't see any step by step instructions except Note 4 that says to loosen the clamp on the throttle shaft and move roller to meet the cam.

 

[FillupD]

Re: Can't adjust timing, Timer base repalcement?

http://www.youtube.com/watch?v=S9ryBVGlATo

This is not my motor but this is how it performs on mine. It looks like everything is working OK.

 

[FillupD]

Re: Can't adjust timing, Timer base repalcement?

Ttt

 

[tashasdaddy]

Re: Can't adjust timing, Timer base repalcement?

No, the timing plate is not moving as it should. i have a 80's 50 that was doing that, sprayed WD 40 under the plate and work the timing plate, took a lot of wd 40 to wash the crud out for the plate. i don't have a 73 manual.

 

[Joe Reeves]

Re: Can't adjust timing, Timer base repalcement?

I see nothing here about cleaning and rebuilding the carburetors, along with manually inspecting and cleaning the high speed jets.

Playing around with the full spark advance timing stop screw is a excellent way to melt a piston. Put it back where it belongs using the following method.

(Timing At Cranking Speed 4?)
(J. Reeves)

NOTE: If your engine has the "Fast Start" feature", you must disconnect/eliminate that feature in order to use the following method. The "Fast Start" automatically advances the spark electronically when the engine first starts, dropping it to normal when the engine reaches a certain temperture.

The full spark advance can be adjusted without have the engine running at near full throttle as follows.

To set the timing on that engine, have the s/plugs out, and have the throttle at full, set that timer base under the flywheel tight against the rubber stop on the end of the full spark timer advance stop screw (wire it against that stop if necessary).

Rig a spark tester and have the gap set to 7/16". Hook up the timing light to the #1 plug wire. Crank the engine over and set the spark advance to 4? less than what the engine calls for.

I don't know the full spark advance setting your engine calls for, but to pick a figure, say your engine calls for 28?, set the timing at 24?. The reasoning for the 4? difference is that when the engine is actually running, due to the nature of the solid state ignition componets, the engine gains the extra 4?.

If you set the engine to its true setting at cranking speed, when running it will advance beyond its limit by 4? which will set up pre-ignition causing guaranteed piston damage! You don't want that to take place.

No need to be concerned about the idle timing as that will take care of itself. The main concern is the full advance setting.

Be sure to use your own engines spark advance settings, not the one I picked out of the air here in my notes.

 

[FillupD]

Re: Can't adjust timing, Timer base repalcement?

There was a rebuild kit installed in both carbs and I put them back on. Still had the samr peoblem so I removed them again and soaked the high speed jets/bowl and made positively sure they where clean. I then installed a gas filter on the line going to the fuel pump to make sure fuel was clean.

I performed the timing check as per the link that tashasdaddy referred to and I got it set OK. When I set it in the water, I just backed my trailer in and submerged the motor. I checked the timing at 2500 (because thats as fast as it would rev) and it was at 19 (close) it was kind of hard to tell exactly but it was close to 19.

Thanks for your help. I really don't mean to be a pest but I'm just confused and frustrated.

 

[FillupD]

Re: Can't adjust timing, Timer base repalcement?

OK, I'll take a look at the timing plate. The manual states that there is a brass bushing there but mine looked clean and I sprayed it with gunk carb cleaner. That is where I will go to next. I will make sure that the timing plate is free and moving. It looks like it is moving, of coarse I don't know what it looks like when it is moving "Correctly".
I'll get it cleaned up and report back, Thanks

 

[Joe Reeves]

Re: Can't adjust timing, Timer base repalcement?

Are you by any chance trying to set the timing by giving that engine full throttle in NEUTRAL?

 

[FillupD]

Re: Can't adjust timing, Timer base repalcement?

I'm thinking about the timing plate and it hits the rubber stopper pretty much where ever I put it except when I screw it almost all the way in. Would this timing plate movement make my coil output go from 18,000 to 12,000 when reved?

 

[tashasdaddy]

Re: Can't adjust timing, Timer base repalcement?

that i don't know.