1982 tower of power timing questions

[jimmbo]

A lot of engines are timed, and linked and sync out of the water, It doesn't have to be running to set the timing, max, or pickup. The water pump should be getting water(muffs, tank, lake) so as to keep it from self destructing.

Idle mixture, and setting the idle speed need to be done with the engine under load(in gear with prop), either in a test tank, at the lake or river on the trailer deep enough for the boat to be not quite floating, or floating and tied securely to a very immobile dock. Setting the idle speed will require the throttle cable to be free, Once the set is set, the cable length will need to be adjusted to have some preload(pressure) to hold the linkage against the Idle Stop. Too little and a consistent Idle will not occur, Too much and it will be hard to shift out of gear

 

[Mybiggles]

finished the carbs and threw them on. I couldn't find a bucket big enough to put the prop in so the idle mixture is still 2 turns out. I was by myself and didn't have anyone to crank the motor over so timing is still at what it was before. Its idling higher then it was before (around 1000rpm) but sounds decent, and no immediate signs of fuel leaking out. One of my linkage arms between carbs is cracked so ill have to order a replacement for that.

I also have a new issue where its not turning off with the key. When I redid the wiring on the boat I didn't touch anything on the harness side so im not too sure whats going on with that. When I get a chance ill pull the key and check the wiring, The only part of the harness I touched was the purple output wire from the key which is accessory power which I hooked to a relay to trigger for all my accessory buttons. I also wired the gauges into that output, beyond that ive touched nothing on that circuit so im a bit confused.

 

[Mybiggles]

Hey guys. Been busy with other projects so havnt had much time to play with the boat.

i'm currently trying to confirm tdc..I saw in a YouTube video where a guy suggested using a piston stopper and marking both directions on the flywheel where the piston bottoms out and then counting teeth. Anyways I ordered the stopper and I'm working on it right now. I have 23 teeth between each mark. When I rotate the flywheel back and line it up in the center of the 2 marks the timing pointer was left of the 0 pointing just before 3 degrees. I assume left is advance and right is retard?

Is this method accurate enough or should I try another method. When I hold the stopper in the cylinder against the piston and rock the flywheel back and forth it doesn't really feel like it moves until it hits each tooth (tooth 11 and tooth 12) which makes me think I'm pretty close to where I should be. Should I just trust it and reset my timing pointer?

 

[Chris1956]

A piston stopper is fine. That is a Johnnyrude tool, but it should work. You are just trying to set your timing pointer to an accurate TDC. Merc does it a different way.

Merc used the .464 inches before TDC to set the timing pointer. This located TDC more accurately, in their opinion.

So set motor to TDC with a screwdriver in the spark plug hole of #1.

Measure from top of piston to top of waterjacket cover.

Add .464 inches to that measurement.

Now turn motor until timing pointer points to .464 inches on timing decal to get close to TDC minus .464 inches.

Measure from piston to top of water jacket cover, and adjust flywheel until piston position matches your sum.

Adjust timing pointer to indicate .464

 

[Mybiggles]

A piston stopper is fine. That is a Johnnyrude tool, but it should work. You are just trying to set your timing pointer to an accurate TDC. Merc does it a different way.

Merc used the .464 inches before TDC to set the timing pointer. This located TDC more accurately, in their opinion.

So set motor to TDC with a screwdriver in the spark plug hole of #1.

Measure from top of piston to top of waterjacket cover.

Add .464 inches to that measurement.

Now turn motor until timing pointer points to .464 inches on timing decal to get close to TDC minus .464 inches.

Measure from piston to top of water jacket cover, and adjust flywheel until piston position matches your sum.

Adjust timing pointer to indicate .464

With the piston stopper in place the mark I made on the cowl didn't fully line up with 2 teeth. what I did was bottom the piston out one direction, mark the cowl and a tooth, rotate the engine the other way and then when the piston bottomed out I marked another tooth and put another mark on the cowl at that point. there is roughly 1/8" gap between my 2 marks on the cowl. I then counted the teeth and divided the number in half which put me in the middle of 2 teeth. I rotate that until the middle of the 2 teeth were centered between my 2 marks on the cowl. I then had a friend hold a screw driver on the piston while I rocked the flywheel back and forth slightly and he didn't notice it moving for a degree or so in each direction. To me this makes sense that Im at tdc. I then reset the timing pointer to 0 degrees. I havnt thrown a timing light on it yet or changed anything. I just wanted to confirm with people that know better before I set it too advanced by accident and seize the motor.


So you are saying the pointer should be at .464 and not at 0? I read some thing about .464 but wasn't too sure what it was talking about. it was my understanding .464 was a reference to find tdc. you would set your dial gauge to where the piston bottoms out then roll it backwards to .464 on the dial gauge and then set the needle to .464 . tdc is .464" away from that mark correct?

 

[Chris1956]

Merc uses the .464" measurement to remove the inaccuracy of finding TDC with a dial indicator (or piston stop tool).

You said that checking TDC with a screwdriver showed a degree or two of flywheel movement, no movement of the piston.

Mercs .464" timing sets the firing point to a single degree, although I am not sure what one. When the flywheel is set to .464" before TDC, the timing pointer should indicate .464".

I doubt it will make any difference as your method to achieve TDC sounds plenty accurate enough.

 

[Mybiggles]

thanks for all the help guys. im going to try and get the timing dialed in today and hopefully take it out tomorrow and link the carbs. May have all been for nothing though as I might be upgrading it to a Evinrude oceanpro 150. from what im reading they are pretty bulletproof motors and the hp bump will be nice! its also a v6 vs straight 6 so the ski pole will be tall enough to clear the motor and I wont have to remount that. should get me closer to the 60mph mark I dream of lol

 

[Mybiggles]

This thing is driving me crazy. Just spent like 3 hours messing with it. I'm not getting spark on cylinder 1 and 5 all of a sudden. I just ripped the flywheel off and pulled the stator and trigger. I cut the shielding off and inspected the wires which are fine. I tested the resistance ratings for the trigger and they all seem to be fine according to the specs I found. I checked the coil and I'm not getting any resistance or continuity on the blue and blue\white wires. The red and red\white are at 146.6 and 145.5 which is a lot higher then the spec I found. Seems like the stator is dead but its odd it's still firing 4 of 6 cylinders. Is there any common link between 1 and 5?

From my understanding the brown trigger wire is used for cylinders 1 and 4 so it doesn't make sense to me that 1 would work and not the other. When swapping the trigger wires on the coils spark and lack of spark follows the feed so it's not the coils.

 

[Mybiggles]

Right well I fired it up after putting it all back together and cylinder 1 and 5 magically started firing. When I grabbed the number 5 wire with it running I got a shock so it's probably just the plug wires making me chase my tail. Stator may or may not work I really have no idea but doesn't seem like it's in spec. Regardless I got the timing set properly. The pickup is at 7 degrees and the max advance is just under 21. Advance was at 18 and the pickup was around 4 originally. Seems to rev smoother and quicker like this but I'll need to take it out and link the carbs and see how she goes. Still waiting to hear back about that evinrude 150 so may or may not keep this thing.

 

[Mybiggles]

I continued having issues with cylinder 1 not firing so i replaced the switch boards which seemed to help fix that problem.

I finally got a chance to bring the boat out today. it was fairly choppy and long story short the boat was taking on water, all the electrical shorted out and I was probably 10min away from sinking by the time someone rescued us.​

Before all that happened I got a chance to test the new prop. I had 3 adults and 3 small children on board. Hole shot was a bit better and it got on plane a bit quicker and was able to keep plane at a bit lower speeds then before. The new prop is a turning point 13.25x17 3 blade, the old prop was a damaged 17 pitch stock mercury 3 blade aluminum prop. Top speed was still around 35mph and I finally had a working tach this time and I was topping out at 5000rpm so i may need to change up the prop again.

Before i swap the prop theres a couple other motor related issues im having.the carb bowls still dont hold fuel in them. if the boat sits for like 5 minutes all the fuel drains out and i need to pump the ball again. I noticed when i pumped the ball when the motor was trimmed up at shore the fuel just poured straight out of them. I just had a mini jet boat for a few weeks and that motor would hold fuel indefinitely and it was extremely easy to start. Is that normal for these carbs? i just rebuilt them and replaced the floats and everything and i was hoping i wouldnt have that issue anymore.

Next problem is my fuel pump seems to be crapping out. Sometimes it works, most of the time power is in and out and occasionally the motor will just die out unless someone is pumping the ball. seems to work better at mid-3/4 throttle then full. when at full throttle and it starts to cut out i can drop the throttle and then bring it back up and it seems to recover. looks like i need to rebuild that

Last question is can a faulty stator, or bad plug wires have much impact on performance? my stator tested way out of spec with a multimeter and im not sure its even working. plus the plug wires gave me a pretty big shock when i grabbed them with the engine running the one time. could that affect my wot rpm or is it more likely the prop selection for my boat?​

 

[Chris1956]

OK, lets answer questions from paragraph 3, 4, and 5 of your post.

Carb bowls always drain when motor is tilted (should be no leak when trimmed). You will see the black catch basin and drain hose under the carbs.

Carbs should not leak when in upright position. Your carbs usually have a brass plug at the base of the carb barrel, and a hex bolt at the base of the bowl. These can leak. The hex bolt requires a gasket. The brass plug is tapered. Make sure the brass plug is tight and cover with wifey's nail polish, to seal it.

Fuel pump on that model should work fine. Did you rebuild it? If not, you should. Make sure pulse lines are good and well clamped on both ends. Also, pulse lines can have springs on their insides to keep them from collapsing. Make sure transfer port covers are tight and not leaking vacuum. Make sure all fuel line clamps, filters and fuel lines are in good shape and tight. You cannot have any air leaks in the fuel line.

Obviously, spark leaking from the spark plug wires will affect firing of the cylinder. I recommend you replace all spark plug wires. They should be avail aftermarket. If your stator was not working, you would not have any spark. Ditto the trigger. I would replace the spark plug wires and retest the motor. No sinking is permitted. (smile)

 

[Mybiggles]

I've done a bit more work on the boat. Ive rebuilt the fuel pump, what are the pulse lines you are talking about? when I replaced the switch boards I noticed a hose behind that panel was broken and I replaced it, looks like it ran from the top of the motor to the bottom. i also replaced the stator with a 16 amp one (hope it works) and starter solenoid. When the boat was partially sinking the #6 cylinder filled up with water and hydro locked which fried the starter solenoid. Compression on that cylinder is in line with the others so it doesn't look like any serious damage happened and cylinders look good through a scope. I've started it up since and it runs well with no odd noises.

The brass part the drain plug threads into either had no sealant around it or had came apart from its sealant and was leaking. I replaced it and put on some proper marine 5200 and im hoping It fixes the leak. I also fixed my bilge pump again and ordered one of those hand pump ones just incase this happens again.

today i pulled the leg and replaced the impeller with a new kit. the new one had a bunch more o rings and gaskets and I kind of just matched what it had on it so I hope im good there. I spent about 30min trying to get the leg back in and I cant for the life of me figure it out. it feels like its binding on something. I've gone as far as grabbing the shift shaft with some pliers and wiggled it into the upper shift shaft and lined that up (i dont understand why its not keyed to only go one way). I believe that part of it is good but I cant get it to slide up much further. ive tried wiggling the flywheel and even cranking the starter while having someone try and force it up (read online about this trick) with no luck. I can only get the top of the studs about level with the top of the holes they poke out of. anyone have any tips for this?

 

[jimmbo]

Some fuel pumps had hoses to the crankcase for the pressure-suction pulses to operate the pump, other pumps are mounted on the side of the crankcase and are sealed with a Gasket. I'm not sure what year merc moved the fuel pump from the upper surface of the Cowl Pan, to the Port side of the block
Did you rotate any of the shafts, rotate the flywheel, or move the gearshift lever at any time while the case was off?

 

[Mybiggles]

mine has the gaskets mounted to the side of the motor

Not originally. i started rocking the flywheel to try and get the splines to line up when I couldn't get them together. I also tried wiggling the shifter forward and back but have it in neutral. The shift shaft on the gear case feels like its spring loaded when spinning the one direction. ive rotated the shift shaft slightly forward and backward but its in the same general position it was when I pulled it out. It think it was preloaded or something and when I pulled it out it rotated on its own. was it meant to be in forward or reverse or neutral when I pulled them apart? when its all lined up properly should they just slide together easily?

 

[jimmbo]

The shift shaft rotates a cam that pushes against a spring loaded pin that is coupled to the clutch dog, so it is going to feel like that

if you lift the shift shaft, it will come out of the cam, and the spring pressure will push the cam forward, and to put the shaft back in, the case has to come apart

 

[Mybiggles]

I lifted it slightly, maybe 1\4", didn't feel like any spring tension lifted off or like it came out of anything so hopefully I'm good there.

​am I correct in assuming it should have a slight preload in neutral? At its resting position the splines didn't line up with the upper shaft

When everything is lined up should it just slide in easily or does it need some persuasion?

Does the prop shaft line up into the power head perfectly when you slide it up or does it need to wiggle into position? The upper shift shaft on mine is free floating and I need to move it with my finger to line it up with the gearcase side

 

[jimmbo]

The Spring is what pushes the Dog to engage in Forward, the preload(tension/pressure) is higher in Neutral, and higher still in Reverse.

When everything, shift shaft, drive shaft, water tube, and studs, are lined up, they should slide together with only the Friction of the groumet on the water tube.

I remember a plastic guide that was also part of the Reverse Lock on the non power tilt models that centered/guided the upper shaft upon installation

 

[Chris1956]

yes, there was a plastic cast piece that fit into the midsection, and held the shift shaft in the right place. They do fall into the gearcase. If you have it make sure it is installed in the midsection. Stick it in with some grease.

If you don't have it, maybe a needle nose plier on the shift rod, where it is exposed to the outside can move it into position.

It is easiest if motor and gearshift are in neutral. The gearcase fits tightly to the midsection, so top -to-bottom wiggling are necessary. I use finger-tightened nuts to hold the gearcase on while wiggling. No wrenches until the gearcase is mated.

You have the plastic water tube extension on the waterpump, right?

 

[Mybiggles]

Didn't see any kind of extension on the water pump housing but there is a tube that comes up maybe 2" from it. It matched the one that came out of it...

I didn't notice any kind of plastic holding the upper shift shaft into position. That shaft can be moved with a finger from the top where the speedo hose comes out so it's not the end of the world. I just don't get why it won't go up. I can't get it in far enough to get nuts on. I've gotten the splines in the shift shaft lined up and had someone wiggle the flywheel and even braap the starter when putting force on the gearcase trying to pop it into the splines. Feels almost like it's hitting a wall.

 

[jimmbo]

Did you grease the splines? A bit of grease on the actual splines is fine, but any on the end of the shaft will cause a Hydro Lock