1977 Ski Nautique Rebuild

Just curious, did you ever modify the timing slot? I only ask because I only get 12 degrees of advance and my secondaries aren't opening either. I've confirmed that the vacuum passage is clear (blew solvent threw and watched it come out in the primary), replaced the cork gasket and confirmed that the plunger holds vacuum. My secondary shaft moves freely so I don't think that's the problem. Like you, my boat goes like a bat out of hell if you manually push on up on the rod at WOT.

Part of me is wondering if our shared timing issue is prevent us from reaching enough engine vacuum to open the secondaries.

Well, i got the boat out to Marty's daughters birthday party on the lake yesterday and had him ride with me to try and diagnose the backfire/missing issue. We figured it out the secondaries are not opening at all. We can manually engage the secondaries while running and the boat picks up speed and power tremendously. Any suggestions on what to do about that?

Could you possibly post what he has sent you? I'm curious because I'm in the "same boat". I only get 12 degrees advance, but I am really hesitant to modify that slot because too much advance and bad things happen to good engines. It seems like a crapshoot and very annoying to keep taking that plate out to extend the slot, and then experiment again.

Those slots are no match for a dremel & steady hand! Go for it.

That's interesting. I didn't know that. Could be the advancing issues. I'll have to research that more.

catamount wrote: HatterBee wrote: Well guys I did a thorough river run today and I believe I just about have most things worked out. I have mounted all the seats and engine cover back in and have all misc items reinstalled. I am however having a backfiring issue. I can run a long time at 3000 RPMs no matter if I ease it there or gun it there, but once I get over 3000 RPMs the thing backfires until I reduce engine speed to 3000 or less. Any ideas on what could cause this? Did lubing your weights clear up your 10 degrees of advance issue? How much advance are you getting at 3000 now?

No not really. I am still at about 12 to 14. I am going to keep playing with because I still have a backfiring issue over 3000 RPM's. I am going to reset the initial timing back to about 12 because it seemed real to hard to start last time once it got hot.   It doesn't happen in the yard only under a load on the water. I have replaced the cap and rotar, and reset the points gap but nothing. It doesnt seem as bad but still there. I have a new set of points and coil and plugs I will through in there and then reset everything and see how that does. If that doesnt fix it I dont know what to try next. However, it runs real good up to 3000 RPM so at least it is working ok because at 3000 RPM I am still running about 32 MPH.

I vote for secondary circuit plugged up.

Secondary fuel level set too low?

Sounds good anytime. I have moved however, I now live in Burgaw which just east of White Lake.

Non detergent oil like a 30 w would be ideal but not worth buying a qt for! Just use a few drops of regular motor oil on the felt wick and just a drop on the weight pivots.

Ok so I had a little time and I took the T-stat out it is a 160. I put in a pot of water that was real close to boiling and it did not open. So I let it get to a boil and after about 30 seconds it finally opened. I would think it should have opened sooner than that. Either way I believe I will replace it with a 143.

Took the rear bowl off the carb just like the carb guy suggested and there was a little trash in there, so I cleaned it out real good and made sure the needle and seat was closing. Hopefully this will take care of that.

I took the dist cap off and looked inside the dizzy. It all looks pretty new and clean to me. I'm not sure there is anything I need to do here but maybe a little lube. Which brings me to the question of what do I use to lube it. The advance seemed to spin out smoothly and return. Can yall think of anything else to look at in there.

I'm going to try and run it some on Sunday in the yard and double check the timing and adjust the mixture screws and idle.

I got the sachs from skidim and I had to cut it down. The way you describe it, it does make a little sense. Just confusing that a new damper would make such a ruckus.

Thanks Tim I will do that with the thermostat. Should I be getting that temperature difference from the intake, block and heads if the cooling system is operating normally?      

I will also check the tach readout with the timing light at higher RPM's.

When I rebuilt the engine and got it all back together is when that transmission noise started. I dont remember if it was there before (remember I have never had this boat in the water, but did get it running before I tore it down.) I removed the transmission to try and eliminate the engine as the source of the noise. It did not make that noise without the transmission bolted on the engine. I did not remove the damper from the engine and there was no noise.

We will see how that plays out.   But first the cooling issue and timing.

TRBeng wrote --- Congrats Allen, any time you make it back go the dock/trailer under your own power on a shakedown cruise, that's a big success! Especially on a project of this magnitude.

1. Tell us more about how the temp gauge acted. Would it return to 140 when returning to idle? If you kept running faster, would it hold 180-190 or would it go hotter? (200 is about all I'd push it.) a 160 stat may run closer to 180 all the time- a 143 would have you closer to 150-160 for the most part.

** The temp gauge would stay around 150 to 160 when at idle and move very quickly to 180 to 190. At this point I shut it down so dont really know if would keep climbing. It would cool back down though but took a while to get back to 150 to 160 range, never as low as 140. The temp gauge seemed to be pretty accurate due to using my IR thermometer right there at the sensor. I might pull the stat and check and if its a 160 might change to 143.

2. If your dizzy is only advancing 10 deg then that will probably cause you problems. Pop the top off and get down below the points baseplate and inspect the weights and springs. Free them up if necessary and lube them up.

*** I will pull the cap and check the weights and springs. Is this something that can be replaced easy?

Hopefully you have an inaccurate tach or speedo (or both) as 30mph at 4500 is way off. That prop/hull/transmission combo will track darn near 1:1 speed vs rpm, so 4500 should get you 45mph. If not, you may have transmission issues after all. Get a shop tach and check yours, and bring a gps with you on your next trip out.

**** I used a GPS to get the speed. The speedo's where fairly close to the GPS reading. I used the tach reading from the timing gun to range the boat tach and it seemed to be close, but I didnt check at higher RPM's, I'll do that as well.

3. A bad transmission usually won't make a sound (they're hydraulic, after all)... Noise from the tranny area usually means damper plate, which is the connection between the engine and tranny. You have to pull the tranny off to access it, but it's easier than a full rebuild and a heck of a lot cheaper. Might want to order one to have on hand in case it ends up failing completely. Ebasicpower sells the good Alto/Sachs damper for a velvet drive for $90-100.

****** I put a new damper plate on when I had it apart. I dont think the sound is from the front, it seems to be towards the rear. This is not an issue I am as worried about right now. I'm more concerned with getting the engine running efficiently and then I will try to work on the gear.


4. Like Brian alluded to, you don't necessarily need for the packing to leak. The gore text stuff is very good. So long as the leak rate is not excessive and the packing gland isn't getting hot, then you're good to go.

*** This is good news, I wont worry about this anymore.




Bri892001 wrote -- 1.) Might just be a thermostat problem. But, also, the thermostat doesn't control the water going to the exhaust manifolds, so they should always be getting water. Hmmm, I'd check to make sure you don't have any restrictions anywhere in the water supply, like in the tranny cooler etc.


**** I didnt check for restrictions. The tranny cooler is new and all hoses are new, I can check them thought to make sure no bugs or what not have made a home over the winter. The exhaust manifolds stayed cool the entire time.

2.) On the speed, are you sure your speedos are correct, have you GPS'd it?


**** Yes I used a GPS.

4.) Depending on what kind of packing you have in there, it may not really leak. I don't think the modern goretex stuff really does much. Of course, there's always the dripless setups. The rudder is fine not to leak anyway, cause that's not rotating constantly like the driveshaft. Long story short, you're probably fine.


**** This is good I used the gortex.



Thanks guys

1.) Might just be a thermostat problem. But, also, the thermostat doesn't control the water going to the exhaust manifolds, so they should always be getting water. Hmmm, I'd check to make sure you don't have any restrictions anywhere in the water supply, like in the tranny cooler etc.

2.) On the speed, are you sure your speedos are correct, have you GPS'd it?

4.) Depending on what kind of packing you have in there, it may not really leak. I don't think the modern goretex stuff really does much. Of course, there's always the dripless setups. The rudder is fine not to leak anyway, cause that's not rotating constantly like the driveshaft. Long story short, you're probably fine.