Lots of steam in exhaust

[Leon_vanos]

I have a new RWC rebuilt a-4 from Moyer marine on a Newport 30 in Long Beach ca. I had a complete blockage in the manifold water exit brass fitting which cause all the seals in my water pump and accessory drive to blow out. After replacing the the water pump and accessory drive I have no more water or oil leaks. The engine runs at 160-200 degrees while under load. It might overheat more but I start to let off the throttle when it gets around 200. I get a lot of steam once I hit 150 and above but when I pull back the throttle the steam lessens a lot. I thought that it could be my exhaust elbow leaving the manifold so I replaced that with the Moyer marine exhaust elbow designed for the Catalina 27 and also replaced my old vetus waterlock. I am still getting a very uncomfortable amount of steam while running under load and running hot. I’ve checked for blockages in the manifold, the block, and my through hull. No blocks and I get good water flow coming out of the exhaust but it seems to lessen at high temps along with more steam. I’ve done a compression test and got 90 on all cylinders. I’ve done a pressure test and the water jacket held 15 psi for about an hour. Not sure where I should start to diagnose now. Also I am getting a lot of smoke out of the oil fill at high temps. Also getting some black sooty spark plugs and cylinder 3 there seems to be evidence of water rust on the top part of the spark plug near the cap. Just recently the engine stalled out suddenly under load during a dock test and started right back up but loosing power under high rpm.

While swapping out the accessory drive I accidentally dropped the distributor and the rotor moved a bit but I spun in back into position (at least I think) and reinstalled it and the engine fired right up.

https://youtu.be/Q4-TVotkqqY?si=27qJKHSnv2gEsXXl

-Leon

[Dave Neptune]

Leon, first welcome to the MMI Forum.

That is indeed a lot of steam. You stated you had a blockage and cleared it. That does not mean that there is not more krud floating around and clogging things up at higher RPM's as there is more flow to carry it and block a port. Once the engine slows or is shut off that krud can fall away. A bit more info about your engine would help.
Is the engine FWC or RWC?
Does the engine have a t-stat installed?
Do you know how old the exhaust is?
When you pressure checked did you include the manifold?

RE the smoke out of the cap. You stated you bumped the rotor and twisted it back. Did the distributor move too? Just how did you twist it back?
The centrifugal advance moves the rotor on the dist shaft. You should be able to twist the rotor a bit over 15 degrees and it should spring back smoothly, It should move freely in both directions, does it?? To much timing (to much advance) can cause excessive smoke out of the breather cap.

Once this is cleared up we can get into the lack of power. The lack of power may involve fuel delivery issues to the carb or inside the carb. I suggest a cheap pressure gage to be mounted just before the carb. Also describe your fuel filter set up and type of fuel pump.

Dave Neptune

[hanleyclifford]

If you have the new exhaust hot section from Moyer Marine you have a 1/8" NPT plug on the exhaust manifold flange. Get the exhaust back pressure kit and make sure you have no more than 1 psi at that port. You could have a collapsed exhaust hose. https://i0.wp.com/moyermarine.com/wp...00%2C800&ssl=1

[Leon_vanos]

Thanks Dave!
I had a really rough experience with my first a-4, so having problems with my new one is a bit heartbreaking.

My engine is only about 3-4 months old since i purchased from moyer. I have a Raw Water cooled. I do have a t stat. I removed it to test it and it works. The exhuast section is a moyer marine and about a week old so its in very good conidtion. I pressure tested the manifold and block together. I have a new racor s3227 fuel filter and a electric fuel pump with an inline fuel filter( the one that comes with a rebuilt a-4 from moyer marine).

While replacing the accessory drive i removed the distrubuter with the cap off and rotor exposed and dropped it on the floor. The rotor moved a bit. It did move freely in both directions. I twisted it back by hand and i was able to drop it back in and the dizzy went in the same postion and everything lined up on all my marks. Engine started up normal and the same amount of steam before and after. Also, same amount of smoke comming out of the oil fill and flywheel before and after.(I have read that it is normal to get smoke out of the oil fill while the new rings and breaking in but it seems like a lot of smoke)

Are you talking about a pressure gauge for the fuel? i do have a oil pressure gauge that i need to install.

Thanks Hanley, I do have the nipple. Ive replaced the water exit exhaust hose and the exhaust hose going from manifold exhaust to the water lift but not the hose section that goes from water lift to transom. Ive replaced them with hardwall exhaust hose from my local boat supply store. I have good access to the rear hose, maybe i should replace that one too. What kind of symptoms would i get from a collapsed exhaust hose?

[hanleyclifford]

A collapsed hose would lead to elevated exhaust back pressure leading to the symptoms you have described.

[Leon_vanos]

Hanley, I removed the exhaust hose from the back of my vetus waterlock to my transom and it is in very good condition. It looks like it is new. No evidence of erosion, cracking, or any blockages. It flows very good. So with new exhaust elbow, hoses, and waterlock muffler my exhaust system seems to be working good. Could I still be getting elevated back pressure? Should I still purchase the back pressure exhaust gauge? Thanks.

[hanleyclifford]

Someone please correct me if I'm wrong, but is that waterlock installed backwards?

[Leon_vanos]

I hope not. It put in in the same way the old one came out. Here is a diagram.

[hanleyclifford]

I just checked with a unit I have here at the house and it seems your installation is correct.

[hanleyclifford]

Unless you have a leak in the boat allowing water to get into that spark plug hole I don't like the look of that spark plug. Could be water intrusion internally into the combustion chamber. Do the other plugs look the same?

[Leon_vanos]

No, it is only on cylinder 3. All other spark plugs look like this one.

[Leon_vanos]

Compression test checked out so head gasket must be ok?

[hanleyclifford]

Fora RWC engine your range of 160 to 200 is higher than normal especially since you said you have to throttle back to prevent going over 200. This could suggest a reduced water flow from the seacock bringing in the raw water. Clogs do occur at the strainer outside the hull. Running hot all the time also encourages steam.

[hanleyclifford]

No, it is only on cylinder 3. All other spark plugs look like this one.

I suggest you swap the #3 to another hole and see if #3 hole dirties another clean plug.

[hanleyclifford]

Just to eliminate the possibility, remove both water fittings on the manifold and do a pressure test. Should hold 20 psi.