Bad vernatherm

[rodknee1231]

Just got my power head put back together (73' 135hp) some of you might be fed up with all my posts but im on the cusp of having this old girl 100% i was running on muffs the other day for the first time and i noticed i could on hold my finger on the head for a few seconds. Thought that was a little irregular. On top of water coming out of the seam of the lu and the midsection which ive narrowed down to a bad exhaust seal. I shut it of and checked the water pump(brand new kit) all looked good. So i moved to the vernatherm and pulled it and tested it. Slowly it opens in hot water. Then after a min in room temp water i pull it put and it closes but takes some force. Is this normal or should it close much easier? Also i added a tell tale it was peeing and kinda stopped before i shut it off would the therm cause that ? And am i right in thinking the leaking exhaust seal would be causing water to come out of the seam between the lu and midsection?

 

[oldboat1]

If you use muffs, suggest you run the hose at only about half pressure, and don't operate the motor above about 1,000 rpms. All of the spray or leakage in the pic you posted earlier is probably a result of water pressure from the muffs.

You cannot diagnose temperature issues or much of anything else running on muffs. In addition, the motor can seriously over rev on you (runaway motor). Find a big tub or barrel for it, and run it with water about half way up the leg. Low rpms. Put it in the lake if you can -- better than other options. (I think you said earlier you had recently rigged a replacement system -- can't speak to that, except to point out you need back pressure for most engine testing, and injecting water is not a sufficient test of the pump and cooling system.)

The t.stat is probably OK from your description. Heat up some water in the microwave, maybe 180-200F. Stick the v.therm in with a pair of tongs. Don't let the sensor touch the container or the tongs -- should fully open. Then run it under some cold tap water, and it should fully close. The thermostat should begin to open around 140F and be fully open at about 160F, but it's usually enough to insure it opens when clearly hot, and closes when clearly cold. If in doubt, replace it.

 

[F_R]

Water leaking out where the lower unit bolts up to the midsection is absolutely normal. If it bothers you, you can drop it down a bit and squeeze some 847 sealer in the crack and retighten. But if you look at the forward "point" of that seam, you will see a deliberate drain notch cut in the casting. So, no biggie deal if it also leaks out elsewhere around the seam. Any water coming out there has already gone through the engine and done it's job and is heading back to the sea anyway.

The vernatherm pin is not self-retracting. The spring on the plastic valve pushes it in. And you might note, that spring is quite strong.

 

[emdsapmgr]

The lower exhaust seal between the l/unit and the midsection is there to hold some of the spent powerhead cooling water in the midsection. That engine uses water inside the midsection to quiet the engine while running. If the rubber o-ring type gasket (314937) is misaligned or deformed, it will let extra water flow out of the midsection. It's supposed to anyway, as FR notes-but at a controlled rate. If that exhaust seal does not seat properly when the water pump is re-installed it can leak exhaust smoke out of that seam area, and it can form on the side where the seam is. More of an inconvenience than a major problem.

 

[rodknee1231]

Some great replies guys. Im gonna replace just the vern then just because its already out and i think its kinda stiff to close. My last concern is the heads getting hot is it normal? How hot should they usually get i thought these motors uaually ran pretty cool

 

[oldboat1]

btw, the "rule of thumb" you mentioned in your first post is effective. If you can hold the heel of your hand on the top of the head for a few seconds, temp is likely within range. Idling, you would probably get a surface temp of 120-130F if you used an infrared gun. Shouldn't exceed 160F.