Rebuilding Power Head

[MASTER Brian]

Re: Rebuilding Power Head

I'll check those out, THANKS!!

Gaskets are here and they look correct!! Maybe now I can get this on the water. 8)

 

[MASTER Brian]

Re: Rebuilding Power Head

Also, not sure if they manual states, but I was told it's easier to hook the shift linkage up, when in reverse. Right now everything should be in neutral. How do I shift the LU to reverse?

I know it has to do with the shift rod, just not sure what.

 

[KYHunter2]

Re: Rebuilding Power Head

Im not familiar with your exact shift linkage.

Pushing down on shift rod should be reverse, pulling up forward.

That is from the neutral position.

I may be wrong , i believe, some of the shift linkages , work arse backwards.

If you move the shift rod itself, it should be as I described though.

KYHunter

 

[funpilot]

Re: Rebuilding Power Head

Brian, I always hook the shift rod up in forward, and then cycle it through the entire range of motion to verify that it did indeed hook up correctly. Definitely an easier job with the carbs off, so I would install the carbs after I install the power head. Incidently, and KYHunter may be able to verify this, but I think you don't want to rotate the shift rod more than half a turn as that changes the heght and could affect the ability to go into reverse or forward, but that is a bit hazy in my memory. I once wrote a procedure to remove my lower unit because I'm the kind of guy who forgets:

Shift rod disconnection to lower Gear case.

The book says the shifting mechanism needs to be in reverse. That’s because the shift rod tends to go into reverse when shoving the gear case onto the exhaust case. But, you can’t actually shove the shift rod pin (by shoving the gear shift lever on the engine from starboard to port) when the gear shift is in reverse because the engine block prevents the shift lever from moving far enough.

Remove the prop.

Put the engine in reverse, and turn the output shaft to engage reverse. Remove the clevis. Put the engine into forward and push the lever over from starboard to port to disengage the shift rod.

Tilt the engine and with the trim tab position marked, remove the bolt in the center of the tab, the larger bolt forward of the tab, and the bolt under the tab. The smaller bolt forward of the tab can stay, it holds the anodes in place.

Remove the four bolts on either side of the gear case, the gear case will drop.

To reinstall, make sure the gear shift rod is pointed forward and is ‘down’. You can shift the gear case on the bench by moving the rod. Down is reverse, middle is neutral, up is forward.

Once the case is up, put on two bolts to hold it in place, and with a screw driver, check the alignment of the shift rod.

Move the shift lever on the engine from port to starboard, and then move the gear change single lever power control and assure that the engine is going into forward, reverse and neutral. With the engine in forward, move the bushing into place, and slide the two bellvue springs to port. The clevis pin is easily replaced by spreading it with a screwdriver has you slide it home.


fp

 

[Dhadley]

Re: Rebuilding Power Head

There's a lot of misconception about port deburring. In the SST classes we're not allowed to do it, it's not legal. And there's never a ring issue. That's not why rings break. Once the cylinder is honed that is all that's required technically. If you go over the edges with anything, that's even better. Just don't grind some angle in them. You'll be fine.

As for the alignment tool, we never use ours. We tried it and found out we could align the caps by hand quicker. It's no big deal.

The reason for the 50:1 in the tank as well as the injection is so you'll have time to verify the injection is working. Mark the tank when you start and after a couple of hours the oil should be below that line. If it isn't, the injection isn't working and you should have alarms sounding. If that happens the oil in the gas will give the motor what it needs.

 

[MASTER Brian]

Re: Rebuilding Power Head

Dhadley, thanks!

Funpilot, thanks also for the explanation. I did find a section in here on the LU talking about Shift rod heights. I'll see if I can check mine. It gives me the height.

I installed the LU this morning, but there seems to be one thing I missed. I forgot to check to make certain the water tube entered the waterpump. Is there a way to test that out, with the Lower Unit installed without a PH? Otherwise, I suppose I should drop that LU again. Luckily it's not a hard task. I paid attention to the exhaust housing, but didn't check the water tube. :^ Everything went together really easily.

The manual also states to, "Position the shift rod seal on the shift rod just below the lower engine cover." The picture is poor, but it looks like a donught shaped gasket being installed with a needle nose pliers. I looked on my boat, but don't see this. What exactly am I looking for and where should it be? Does it go around the shift rod? Is it that important? The book says it prevents water from spraying up through the shift rod area onto the PH. If it's missing, it never seemed to be a problem.

 

[MASTER Brian]

Re: Rebuilding Power Head

I was also reading up on the sync & Link adjustments. It states using an "OMC Piston Stop" to keep the piston from moving. It doesn't look like a very complex tool, but is it necessary, or can I use something else to do the same thing? I'll see if I can locate one or even possibly make one.

How likely is it that the timing pointer will need to be set? I didn't move it, when I tore the motor down and someone has messed with all this fairly recently and the motor idled great before.

 

[MASTER Brian]

Re: Rebuilding Power Head

I called the auto parts store and the guy there hadn't seen one in a long time, he said when he's had to do it though he just uses a bolt or pen and marks that with a line.

Correct me if I'm wrong, (want to make sure I understand the manual), but I turn the flywheel about 1 1/2" past the timing pointer, in a clockwise direction and place mark "A" on the flywheel. Then use something to mark the exact height of the piston. Then I continue turning the flywheel in a clockwise direction until the piston is at the same height again and mark the flywheel "B". Then I just find the midway point and make a mark "C". If "C" is the TDC mark on the flywheel all is good, if not, then I rotate the flywheel until mark "C" and the pointer line up, then loosen the pointer and move it to the TDC mark on flywheel.

 

[KYHunter2]

Re: Rebuilding Power Head

I think I mentioned earlier in this thread, about taping the shift rod so it won't get turned.

The length is critical for proper shifting.

I allways check timing point alignment on a rebuild.

More often then not its , ok.

If you do a search for stop tool, the instructions on how to make one, are there somewhere.

The shift rod seal , looks like a 2" X 3/16 " thick , or so , round rubber disk , with a slit in it to go around shift rod.

It goes on top part of shift rod, where it enters the mid-section.

KYHunter

 

[MASTER Brian]

Re: Rebuilding Power Head

You might have, I don't recall. It was left alone, until I pulled the LU out to install the waterpump, then I think it might have gotten moved.

Down is reverse, middle neutral, up forward. Problem is now I don't know where it is. I tried to measure, per the manual, which states 22 1/16" (from memory, may not be correct. I get 21 1/8" when I measure. I'm doing this with the LU installed, but my measurement should be accurate, I'm measuring from where they state to measure and I have it in neutral. I can't raise it an inch, so something must not be correct.

At this point, the PH is installed, I just need to hook up the electrics, carbs, and fuel pump. I can turn the shift rod, but I don't know which way at this point, because my meaurements don't correlate with the book. Is there a way to figure this out, while installed? Can I hook up the shift linkage and run through the shift sequence to figure it out, or is that a pain?

I don't really want to drop the LU again, but if I have to, I have to.

I'll check the point alignment, and look for instructions about a tool.

Maybe the shift rod seal got put with the misc covers. I'll look and if not, sounds like I can easily add that later.

Thansk...

 

[funpilot]

Re: Rebuilding Power Head

Brian, the shift rod grommet seems to be a bit inefficient to me, and I think just getting it in place is all you really need to do.

I'm careful not to rotate the shift rod needlessly. If you haven't moved it much (as in not turned it several turns) I think you will be OK, but you have enough questions in your mind about how you did to warrant dropping the LU and re-measuring. The tolerance given (1/32) is small enough that they are mostly talking about 1/2 a turn. In other words, they want the thing screwed in the proper amount of turns, and the leeway they give is their machining tolerance of the thread form, and the measurement is done in neutral (center detent).

fp

 

[KYHunter2]

Re: Rebuilding Power Head

You are probably fine, as funpilot pointed out.

Hook it up and try putting it in fwd. and rev.

You can tell by trying to rotate the prop.

As long as it didn't get turned much , it should be fine.

It shouldn't get turned just from dropping and installing the lower unit.

Don't worry about it, just get her fired up .

Im anxious to hear how it goes.

As far as the grommet, shift rod seal.

Inefficient , is an undrstatement, LOL.

It just sort of flops around ,on top of the shift rod/ mid section.

I guess it does help keep fish, from hopping into the midsection !! LMAO

Keep us posted.

Good-Luck,

KYHunter

 

[MASTER Brian]

Re: Rebuilding Power Head

Well, I can't find that grommet, so for now, I'm not worrying about it. I'm out here trying to finish the electrical up as we speak, flywheel is left as well as electrics on port side. I also need to install the fuel pump, and carbs.

It looks like I'll be dropping that lower unit, as I did turn it trying to see how much it would give, trying to get it close to the specified amount. Problem was, my wife helped to seat the water pump and I can't/couldn't be certain it didn't move while doing that. I'll probably wait until I hook up some more linkages and see if I can tell that way, but I don't want to connect it all and be wrong. I figure dropping the LU and re-installing is at max an hour job.

KY, I'm anxious as well. So far all has gone very smoothly, besides the parts hang ups.:/

 

[MASTER Brian]

Re: Rebuilding Power Head

If it shifts from neutral to forward and reverse, is it ok. Or not? I obviously can't do this at this point with boat running, but this is all that is left, besides carbs.

 

[KYHunter2]

Re: Rebuilding Power Head

I'd bet you'll be , fine.

As long as you didn't turn it much.

There's a certain amount of tolerance, the 1/32 , is based on new , not 10 year old gearcase.


Granted , the amount of movement to engage the gears, is more or less a constant.


Everything gets a little worn in , including gears, clutch dog etc. etc.

If you really think you need to , drop the lower unit and remeasure.


If you've allready installed carbs, I'd button her up and go on.

When your doing the idle breakin, you can try shifting it while running.

Its your call , but if it were me I'd get her fired up and check the shifting .

It can be adjusted , with out removing the carbs, if needed.

Im sorry misread your previous post on the shift rod length.

Yours is supposed to be 221/16 + - , 1/32, you stated yours measured 21 1/8.

Theres no way it would shift , as you said it did being off that much.

KYHunter

 

[funpilot]

Re: Rebuilding Power Head

Brian,

I'm not certain why they call out such a tight tolerance, and such exacting heights on the shift rod. If KYHunter is correct, it either shifts or it doesn't, which seems logical since there are detents in the shift to locate each position. The proof in the pudding will be if it shifts with the power control lever, which it seems to me you can verify with the LU in place and not running if you get free prop movement in neutral, and then it locks with the power lever in fwd and reverse.

fp

 

[MASTER Brian]

Re: Rebuilding Power Head

Well, I dropped the LU and re-measured. I put it right at where the manual said it should be. It seemed to work fine. Was having some trouble with the control lever, but figured I'd mess with it at the lake. Afterall, I could just unhook and do the initial idle break-in.

Well, she fired right up and I got through the idle break-in just fine. Even seemed to have the gear shift problem fixed, so we loaded the boat into the water, but had no reverse. I did have forward, so we tried that. I didn't have full throttle, but she seemed smooth and was able to get the boat to about 3000 RPM's which was the cut-off point for the 1st hour.

Problem is, that was about all it had. I didn't run it long, but it did run fine, as in smooth. One point, I dropped RPM's down to an idle, then it wouldn't pick back up and go again. There was gas/oil/something on the water surface and it looks like it came from the carb area. Problem is it was getting fairly dark, so I couldn't investigate much.

The shifter linkage, seems to have 3 definate settings, which I would take as reverse, forward, and neutral. Problem is the prop has no catch in what I would think would be reverse. I look at the pics I took and everything appears to be were it should be.

Where could I be off? Could this be my problem?

I had pre-mix in the tank I ran at 50:1 and my VRO seems to be working as the oil level did appear to change. I haven't done a compression test or a re-torque on the head at this point. I'm not even sure a compression would tell anything, if I'm not getting the throttle opened up fully. It looks to be very close to fully opened, but why wouldn't it have full power?

If the shift linkage wasn't right, but the carbs appeared mostly opened, would I not have full power? Maybe a coil is bad, maybe timing needs re-checked. Obviously the gas leak is an issue, so I'll look at that. Does it sound like I have a major problem or not?

Any ideas..... I'm not sure I even want to know at this point!!:%

 

[MASTER Brian]

Re: Rebuilding Power Head

To clear things up, I didn't notice the film on the water, until I was back at the dock, but there was definately gas/oil on the tray under the carbs.

The motor got hot to the touch, but the water-by-pass was cool. Motor was never too hot to not put hands on. Felt about right.

 

[KYHunter2]

Re: Rebuilding Power Head

What was your breakin procedure??

It won't go into reverse , and you verified the shift rod length?

Was the motor shifting fine before rebuild?

You replied earlier , that you verified , it was going into fwd. and rev.

You did do a spark test, right?

How did you set timing?

Gas leaking out of anywhere inside cowling is bad.

Once its in gear , its all in the throttle then.

As far as rpm's.

Are you sure the link and sync. is correct?

You must remember that the slower you break it in the better. I mean follow a good breakin procedure.

Do you have a pressure guage was the pressure where it should be?

You did rebuild the carbs , right?

Some of my questions , aren't directly related to the rpm problem.

But are important , anyway.

I never do the idle breakin and go right to the rest of the breakin at the same time .

I like to break them in a little, then allow cool off period .

Then do it again.

You need to verify good spark on all cylinders.

Timing, link and sync. , carbs , water pump .

Are all correct and operating properly.

The breakin is not the time to be in a hurry.

I really don't see how you've had enough time to break it in correctly.

If you didnt rebuild the carbs your spelling disaster.

KYHunter

 

[MASTER Brian]

Re: Rebuilding Power Head

Break-in procedure was 3) heat cycles per Wiseco. Run engine at idle till reach operating temp, then shut down to cool and repeat. They say that conforms pistons to cylinders. I did this on trailer, backed into water at a small ramp. Had plenty of water, but not deep enough to unload boat.

I then unloaded boat at main ramp to procede to break-in. Figured reverse wasn't real important. Hope I wasn't wrong. I did not have a chance to finish the break-in. I was trying to work on the 1st hour, which is under half throttle. I wasn't trying to go very fast, I could just tell it wasn't as responsive and it needed more throttle than normal to get onto plane.

Yes, it shifted fine before the rebuild. It even appeared to shift until I hooked the linkages up.

No reverse and yes I verified rod length with LU off. It seems to shift to reverse, but the prop seems to be in neutral.

No, have not checked spark at this point, it was there before. I'll check later today, didn't have time, once I got home last night.

Went through the carbs, but didn't do a complete rebuild, as I haven't located some of the gauges it looks like I need. It was obvious they had recently been gone through, which is what the previous owner had mentioned. Also, my failure didn't appear to be a fuel issue. I also verified they were all sync'd up.

Yes, the gas leaking is bad. Initially, I thought it was leftover from the initial priming of the oil and fuel line and I found a line that was lacking a clamp before firing it up. I'm not so sure something else didn't get nocked loose, but I didn't see it when giving it a last look over prior to starting the motor.

Are you asking about pressure gauge for fuel or something else? If so, then no.

What is the best way to check spark on all 6 cylinders? I'm assuming all plugs will need to be out and grounded to prevent firing.