I’ve cranked the engine A LOT with the seacock open

[Sv_quixotic]

Hello all, new to the forum, thanks for being here to help.

I was unaware that cranking the engine with the seacock open was a bad idea. My late model A4 was not starting after this winter, turned out to be bad points. In the struggle to diagnose the problem I spent a few days cranking the engine. Now the engine is running, but I have constant white vapor coming out the exhaust. My original fear was a blown head gasket, and that is still a concern. My question is, could the white vapor be from excessive water in the exhaust? And, how do I drain the water from the exhaust?

A little more history, and things I have discovered.
The wrong thermostat was installed by the previous owner, and I have been using it for the last 3 years.

The engine has had problems with overheating and blowing white vapor in the past, but I have been quick to throttle down (and the temp drops quick) or shut down the engine.

I recently did a compression test. It showed weak compression in all the cylinders, dry 60-65 psi each, wet 70-75. What strikes me as odd is the consistency. No one cylinder is low or high, so I wonder if my tester is off.

Over all the engine starts easily, and runs smoothly. It doesn’t cough or sputter when I throttle up or down quickly, but over long use ( more than 2 hours) it will start to over heat and blow white vapor. At that point I can only putt along at barely an idle (2-3knts).

P.S. I will make an introduction on that thread.

[Peter]

Hello and welcome,

"My question is, could the white vapor be from excessive water in the exhaust? And, how do I drain the water from the exhaust?"

The white vapour could be due to water getting in somewhere it is not supposed to. However, draining anything will not resolve that issue.

"The wrong thermostat was installed by the previous owner, and I have been using it for the last 3 years."

Are you still using the wrong thermostat? Have you replaced it with the right thermostat? Have you removed the thermostat completely? If the latter, have you installed a bypass restriction valve to compensate? Many folks run with no thermostat and a bypass restriction valve installed between the fitting on the water jacket cover on the block and the thermostat housing. Close that valve to give maximum cooling to the engine.

Have you flushed the engine or done an acid flush?

Is it raw or fresh water cooled?

Have you checked the oil? Does it look like oil or has it gotten "milky" - if you have water incursion issues into the innards, the oil will get milky.

Hope that helps - confident others will chime in with more ideas.

Regards,

Peter

PS - Welcome to the club of people who had no clue about raw water intake and engine cranking when they first got their boat. Has anybody ever considered designing a system that tacks this? RPM activated switch that only allows water flow when RPM exceeds some threshold? OR perhaps more simply, a GFS that tells you not to crank too much with water intake open

PPS - a GFS is a giant friggin sticker

[tenders]

If you’ve gotten your engine starting and running reliably now, you’re in the clear for whatever immediate sins you committed while cranking. Further complicating things, the big problems with cranking come with engines with waterlift exhaust systems - waterlifts look like a big plastic or metal teakettle in the exhaust. A standpipe system, a tall metal column, doesn’t have a problem with preignition cranking though I tend to shut my intake off anyway just to be on the safe side. Which do you have?

Agree we need to get Peter’s questions out of the way before proceeding. The details on the thermostat and bypass were covered pretty completely in a thread over the past few weeks. High temperature could definitely explain your white smoke/vapor symptoms!

Consistently low compression could be due to consistently worn valves or rings. Could also be due to a consistently low compression gauge or consistently low tightening of the tester in the spark plug hole. The A4 does surprisingly well with low-ish compression. If you aren’t getting exhaust in the cabin I would personally be worrying about the other things first.

[Sv_quixotic]

Are you still using the wrong thermostat? Have you replaced it with the right thermostat? Have you removed the thermostat completely? If the latter, have you installed a bypass restriction valve to compensate? Many folks run with no thermostat and a bypass restriction valve installed between the fitting on the water jacket cover on the block and the thermostat housing. Close that valve to give maximum cooling to the engine.

I have removed the old t-stat and closed the bypass valve. I’m waiting for the correct 2 valve t-stat to arrive from MMI.

Have you flushed the engine or done an acid flush?

I did an acid flush with the t-stat removed and the bypass valve closed.

Is it raw or fresh water cooled?

Raw water cooled.

Have you checked the oil? Does it look like oil or has it gotten "milky" - if you have water incursion issues into the innards, the oil will get milky.

I checked the oil on the dip stick, pulled the dip stick and cleaned off then re-inserted and checked. And it is not thick or milky, I also don’t smell gasoline.

Something I forgot to mention earlier, I placed a 5 gallon bucket under the exhaust outlet. In a minute, only half the bucket was filled. The pressure out the back seems strong, there are fat gushes that shoot about 18” out the back every 3-4 spurts. I do have a new impeller on the way.

[Mo]

If you get 2.5 gallons idling that's OK...rpms up a bit and she should fill that bucket or pretty close to it. If you don't know when the impeller was changed last it's a good idea to change it and put it on a schedule. I keep two spares on the boat. I generally change them out every 3 years but I'm not big on motor use...end of the jetty and sails are up.

Depending on the outside temperature it can look as though you have white smoke out the exhaust sometimes. Usually spring of the year here in NS and October when the ambient air outside cools...slightly warmed water shoots out into the cooler air and voila.

Another thing you can do is remove a plug after running...each cylinder, one at a time. If one or two plugs look really clean, like you washed them, that might indicate water into the combustion chamber. Sometimes you might see a droplet of water on a plug...gas does not create droplets on plugs, only water does....so you could check that. That said, expect number one and two cylinder plugs to be a little cleaner than 3 and 4...if the plugs have some gas and oily deposits the hope of NOT having a damaged head gasket is better.

Personally, I don't use a T-stat at all and keep my by-valve open 1/2 way. Been running like that 10 years now without issue. I run slightly hotter plugs NGK XR4's and no issues with fouled plugs either. Might want to give that a try and see if it works for you.

[Sam]

I'll add a little extra info since I have a 1966 early model A4 for the last 40 yrs. I learned a few things from trial and error and much from the forum. The early model Dole option thermostat is for 140 F, later models are 160 F. [the historians will tell you that salt deposits do not form @ 140F] Raw cooling with impellor water pump & Dole produces the surges or gushes that you see. I'm guessing you have stand pipe as well. There is a little hole in the thermostat plate that allows a little water to pass even when the water is directed toward cooling the block. this water mixes & lowers the temp of the exhaust gases and in essence turns to steam...white vapor. In Chicago many of us do a spring river bridge run to get to Lake Michigan and our harbors. It would be very unusual for someone not to point out to me "there is white smoke coming out of your exhaust". It is normal for the raw water early model/Dole set up. [A little blue, your burning some oil, black your running gas rich]

[ndutton]

I have removed the old t-stat and closed the bypass valve. I’m waiting for the correct 2 valve t-stat to arrive from MMI

If by correct Tstat you mean the new Moyer Marine manufactured 3 spring thermostat,

please know that the condition of the port in the center of the underside of the thermostat housing dome becomes a factor. Corrosion of the port degrades the thermostat's ability to restrict bypass coolant.