oil mix and whale tail - Paul

[dafox99]

Hey Paul (or whoever wants to respond).<br /><br />I just read one of your posts where you said you run one of your motors at 32:1. Should I be running my '65 40 HP at this same mix?<br /><br />Also, this boat/motor combo came with a "whale tail" bolted on the cavitation plate. My recollection of these things is that it helped to plane the boat better and at lower speed, but shaved a little speed ... yes? If so, do you recommend keeping it on or removing? the boat planes immediately (14' aluminum"<br /><br />Thanks,<br /><br />Dave

 

[Paul Moir]

Re: oil mix and whale tail - Paul

No, 50:1 is just fine for any 40hp. Actually, I wouldn't have any problem with post '61 40hp engines at 50:1. But of course the official year for that is 1964, and I stick to that when people ask.<br /><br />The thing about the 4hp engines are they really can use the extra oil as they wern't given the low friction roller bearings the larger engines have. Those plain bearings need a lot of oil to work correctly, which is the reason you don't see them in any modern 2-stroke engines. <br />As a matter of fact, they don't even have a proper bottom crank seal and rely on oil to seal it.<br /><br /><br />I would think a "Whale Tail" on a 40hp would be a very bad idea, as the cavitation plate is naturally low in the 40hp and so the tail would be submerged even when your on plane. Which will really slow the boat down. I would definitly try it without and see if it works better.<br />Raising the engine up on the transom may give you much better performance. Just make sure the engine still primes (water) at idle and flows at full throttle.<br /><br />Hope that helps!<br /><br />4hp block:<br />

<br />Note the plain bearings on the crank bottom main, crank middle main, and connecting rods. The only roller (and oil seal) is on the top main.<br />Chinewalker suggested the 50:1 ratio on these blocks is why you see so many post '64 3 and 4hp engines with thrown connecting rods.

 

[dafox99]

Re: oil mix and whale tail - Paul

Thanks pal. jeez .. a bit of a cheapo design. Good to know. <br /><br />The whale tail will be ejected in the morning.<br /><br />Well .. while I have you on the horn ...<br /><br />I mentioned I used to wrench at a boat shop backin the late 70's and early 80's. Haven't touched the things since then, but it occurs to me I had all the OMC special tools at my disposal back then. Three items:<br /><br />We had special pullers complete with shouldered bolts for certain flywheels. the shoulders were set so the bolt heads were all exactly the same distance from the flywheel for straight pulling. My generic three-hole puller didn't have the right bolts, so I just bought three 2" 1/4 X 20 bolts to pull the flywheel. I ended up bending them and nearly pulling them (and the new washers) right through the puller brace. Just get stouter washers and try to align everything straighter next time? I remember we torqued that puller like crazy, and then popped the center bolt with a plastic mallet and the wheel would just pop off.<br /><br />Second - We also had a locating ring to position the coils (that I haven't been able to get to yet). We would install the coils, and then slide the ring over them and adjust the coils just until the ring would spin, so we knew the coil/flywheel gap was set. Do I just eyeball that, or do I need some special tool?<br /><br />Finally ... the shop didn't have the points, so I'm just going to sand them a bit if they are burned and replace when I can get some. Do you happen to know the gap on them?<br /><br />Thanks so much.

 

[dafox99]

Re: oil mix and whale tail - Paul

Oh .. check on the engine jacking. Any rule of thumb on where the plate/prop should sit with respect to something like the bottom of the boat? We used to put hydraulic jack plates on high performance boats, I have completely forgotten all the rules.

 

[OBJ]

Re: oil mix and whale tail - Paul

Dave...when setting coils, look at the "post's" the coil sets on....two per coil. You will notice a chamfered edge on each post. Set the edge of the coils flush with the top edge of the chamfer. This will set the air gap.<br /><br />Points are set at .020.<br /><br />A little PB Blaster or good penetrating oil would help losen the flywheel. Yeah....they can be a pain.

 

[Paul Moir]

Re: oil mix and whale tail - Paul

I haven't done a lot of experimenting, so I'll leave it to you on the engine jacking. With modern outboards, you want to run with the cavitation plate at the same hieght of higher than the bottom of the hull. I think you may end up a bit lower due to the crummy water pump. But this is just fun testing.<br /><br />As for the puller, I have a fairly beefy harmonic balancer puller with some thick (~1/8") washers. Three 1/4"-20 grade 8 bolts seem to pull any flywheel off. I just torque it up (~50 ft/lbs), pull up on the flywheel and tap the center bolt, torque it again, tap it again until the flywheel pops. Sometimes it makes a horrible noise when it lets go.<br />105 ft/lbs for the flywheel nut when you tighten it again or the flywheel key gets sheared.<br /><br />The ring isn't necessary - just carefully align the coils to be even with fronts of the machined bosses they sit on. Use a straight edge and you can set them very accurately. <br />My personal method is to set the coils a little too far out, leave their screws a little loose and tape over their faces with electrical tape (~.007"). Then set on and rotate the flywheel allowing the magnet to push the coils back. The armature plate can't be very wobbly for this to work, and it isn't so important on electric start engines.<br /><br />I'm as cheap as they come - I almost never replace the points these days and instead file them with sand paper. I finish them with a real high grit (400+) and sometimes even buff 'em. Gap should be set to open .020" max.<br /><br />The 4hp is definitely a 'buget' engine. But it runs some sweet. <br />I've just discovered that the aftermarket head gaskets for them are .010-.020" (not quite sure but I'm leaning towards .020") thicker than the stock ones. Went from ~80psi to over 90. I guess that makes .01hp though.

 

[dafox99]

Re: oil mix and whale tail - Paul

Thanks so much to both OBJ and Paul. I do remember some mighty profound "pop"s when the flywheel finally let go.<br /><br />Looks like with some stouter washers, some penetrating oil, some sandpaper, a feeler gauge, a torque wrench and someone who can pull 105 ft/lbs I should be in business. I'm thinking McGuiver could probably build a small thermonuclear device with all that. Me .. I just want to fix my boat.

 

[CATransplant]

Re: oil mix and whale tail - Paul

Dave,<br /><br />You have my second on the Grade 8 bolts for the puller. I use Grade 8 washers on it, as well. I've been advising folks who are having problems getting the flywheel to pop off to torque it to 50 lb., tap the center bolt with a non-metallic hammer and then, if it still doesn't come off, just leave it alone with the pressure on it for a day or two. Generally, it will end up popping off at some point.