Rebuilding Power Head

[MASTER Brian]

Re: Rebuilding Power Head

Everything appears in good order, the factory height, just doesn't work. It places the shift lever to far back, to were it hits the block, when all cables are hooked up. I guess it's 20 years of wear and/or rebuilds.

It does shift just prior to the carb opening, just not much prior. It doesn't "bang" in or "jump" out, and I rarely get a grind, so it must be really close there. Either 1 more turn up on the rod or a slight adjustment to the cable. I'll play with the cable 1st.

Thanks for your response to this, it does clear up that my thoughts were wrong. I wanted to be sure.

It opens, just prior to the carbs moving, I'd like a tad bit earlier, but if I get it to not grind, I won't complain.

 

[MASTER Brian]

Re: Rebuilding Power Head

I also thought I should mention my flywheel is done and it was dynamically unbalanced. I guess that should explain my vibration.

Could the sluggish low end be because of plugs? A friend keeps saying that was a classic symptom on his jet-ski motors even if he cleaned them. I don't know how he cleaned them, but I used a spark plug cleaner on mine, which uses a fine abrasive to basically blast the plug clean. My dad says he used to use them when he was younger to clean his plugs, my grandpa was a mechanic. He said he never had any issues, but that was automitive.

I don't mind buying new plugs, but with double oil, I don't want to go through $26 in plugs every time out, if I don't have to. I planned on buying new ones once the break-in is finished.

 

[KYHunter2]

Re: Rebuilding Power Head

If the plugs are really getting fouled, cleaning them will help.

I use a wire brush , whatever , to clean up the electrode.

As long is doesn't damage the plug.

I change mine out, with a set of clean ones, and repeat if needed.

Usually only after the initial fire up / idle break in.

Since I started using the pennzoil , semi-synthetic.

I haven't had a fouling problem , even on the double oil break in, period.

I REALLY HOPE, this statement doesn't get another oil topic going. LOL.

You've got a spark tester, if in doubt .

Test them and see if there performing correctly.

KYHunter


KYHunter

 

[funpilot]

Re: Rebuilding Power Head

Brian, when I mentioned warm weather, I meant that the air is less dense, leading to a lower mass flow through the engine, reducing available horsepower. Check with your friends who are pilots about engine performance on a hot, humid day.

Your plugs should not over foul, even running your pre-mix with your VRO during break-in.

fp

 

[Dhadley]

Re: Rebuilding Power Head

Make sure you're using the right spec for the shift rod height and you're setting it in neutral, not in gear. Once the height is correct the shift linkage on the block should be about straight up and down in neutral.

Are you sure all the bushings are in the shift linkage on the block?

 

[MASTER Brian]

Re: Rebuilding Power Head

I was using the correct spec, the only other one they listed was for an extra long shaft (if I remember correctly) and it was a good 3-5" higher. No way that one would work. I looked at the parts catalog I have and compared to what was on my linkage. Everything appeared to be there.

At this point, in neutral the shift linkage is almost straight up. It's not perfectly straight up, which is why I thought about turning the shift rod up 1 more turn, so that it would be straight up. However, I tested the shift vs. carbs opening again last night and before the carbs start to open, the prop is locked in gear. So I'm not sure I should mess with it.

As for the plugs, it sounds like that shouldn't be the issue, but I'll likely buy a new set and install them once the break-in is over if not sooner. Just to see.

One other thought, where should the timing be set? The manual calls for 30*BTDC, but the front of the motor has a sticker that says 28*BTDC. Which should I use? I split and set it at 25*BTDC when I timed it last time using Joe Reeve's Method. Would 1* off cause a lag?

Also, I couldn't believe how much they took off my flywheel. He said it was hard to balance. Maybe it's not as much as it looks, but there are about 4-5 spots on each side where they drilled it to balance it.

 

[MASTER Brian]

Re: Rebuilding Power Head

I was looking into the trim/tilt gauge and I am starting to think my issue with it lies in the sending unit. I sprayed it with some WD-40 and with power on, boat off, I could get it to work fairly accurately when moving by hand. I'm not sure if there are contacts on there that can be cleaned or if they are even very expensive, but at least I've narrowed that issue down. The unit works fine other than the gauge, so it's not a priority right now.

 

[KYHunter2]

Re: Rebuilding Power Head

Bryan , Part of my post about checking your plugs, was Hooey!

Sorry about that , It was late and my mind was asleep I reckon.

If you read the breakin procedure, I copied from maxrules.

You'll see what he recommends, I go by the manual.

You are talking about setting the timing at WOT,.

To check against what it is set at now.

Joe reeves method is usually very close, or right on.

But , you need to verify, and possibly adjust.

What I'd do , is remeasure the shift rod length .

And as Dhadley said , make sure all components are there and where they belong.

Then do a link and sync. from the beginning.

If you get the shift rod length right , and do a complete link and sync.

Then we can rule , these out, if you still have trouble.

I mentioned to you before , about the link and sync. , NO Deviation, from procedure.

As far as trim guage , I'd worry more about getting your boat set-up / running correctly.

I used the hole my trim guage was in for a water pressure guage, still havent put the trim guage back.

I doubt if I will, never really had much use for it.

The tach, feel, and sound , are my trim guage.

Plus , with my eyes glued to the pressure guage, and trying not to run anything over.

I dont have the extra eye, to watch it anyways. LOL

Factory stuck the trim guage , right where, the pressure guage, needed to be .

So , I can watch , tach and press. at the same time.





KYHunter

 

[MASTER Brian]

Re: Rebuilding Power Head

KY, I have dropped that LU now twice just to recheck the shift rod height. Each time I've done it, I've double checked it 2 if not 3 times before putting the LU back up. The spec in the book, just does not measure up. Not sure why, but it doesn't. I was planning on turning the rod up 1 more turn, so it would be at 3 turns up, but I'm not sure it's needed. I messed a bit with the linkage itself, but I think I made it worse in reverse, so I'm going to undo what I did and/or go the other way. If that's no better, than I'm going back and turning it up to the 3 turn. I really don't think dropping the LU again will solve anything. I hope I don't sound unreasonable, I just hate continueing to drop it. I'm worried the more I do, the better chance of ending up with stripped threads. Maybe I shouldn't be worried, but it seems like any time a part needs taken apart in an aged aluminum housing I end up with something being stripped. So far that hasn't happened on this boat, but I feel like it's going to happen any time. And like I said I've done it at least twice with the same results.

With all that said if you guys still think I'm crazy for not dropping it again, let me know and I'll do it. It's not that difficult, I just worry and I don't seem to end up at any different findings.

I understand your stance on the trim gauge, I just think it's nice for telling others where to set the trim, if they aren't real familiar with the boat. My wife for instance or if someone else is pulling me skiing. At this point I don't plan on messing much more with the trim gauge, unless it's just a side thing.

I did find my carbs weren't opening up completely, so I re-adjusted the throttle stop and that seemed to help. I had a friend help me do the initial link and sync and either the throttle stop didn't get set right or it just needed re-adjusted. I do want to verify that the throttle pin should be straight up and down. At this setting the butterflies are perfectly horizontal in the throttle opening. Is this where they should be?

The last thing is I still need to know where to set that timing? Should it be per the manaul at 30* BTDC or per the carb cover at 28* BTDC? Once I get an answer there I will proceed to repeat the entire link and sync process.

I hope I haven't missed anything and once again, thanks a bunch! You guys are life savers!!

 

[MASTER Brian]

Re: Rebuilding Power Head

I am also curious how I check the prop/hub. Am I supposed to do this by looking at the end of the prop or somewhere else on the prop?

 

[MASTER Brian]

Re: Rebuilding Power Head

Did another sync and link and it's running better. The low end bog is just about gone. There is still a slight hesitation when it's been idleing. I'm not sure if something is missing just a bit (as in an electrical issue) or if it's just the extra oil/fouling plug. It stutters and then clears out and goes. If I'm moving at a higher idle, then it doesn't seem to do this.

I also noticed the idle isn't as smooth as it was prior, so that needs to be messed with a bit, but that shouldn't be much of an issue. A few times when shifting it now wants to die out. I'll just re-run through the idle adjustments. I was going to try to put a timing light back on the idle tonight before leaving the lake, but rain started to move in.

During the link and sync, I found my timing point was off just a bit, so I re-set that and then did another timing using Joe Reeve's method and that was off a bit as well. Not really sure how much it was off with the change in pointer, but it was off some.

I had also made some changes to the shift linkage, wasn't better when out on water, but I played with it some while on the trailer in the water and I think I got it to where there is no grinding at all.

I plan on getting back out tomorrow and finish running the double mix, switch to fresh fuel, install new plugs and recheck my timing once more and I'll post those results.

BTW....since I still don't know whether to go with 28* or 30* BTDC, I set it at 24* using Joe's method. I figure they wouldn't have put 28* on the carb cover, if that wasn't right. ....and I'd rather be safe than sorry!

I also didn't notice any cavitation feelings, but it was fairly rough out.