Steam From Exhaust Ports

[Outrage 19]

Is it normal to have steam coming from the exhaust ports under the tell tale. The tell tale has a steady stream of water coming out, I can put my hand in the stream, it’s hot but not scalding. Also from reading past posts I remember some one saying if you can hold your hand on the head for more than 3 sec it’s not running hot. Call me paranoid but I don’t remember steam coming from the exhaust ports before.

 

[Outrage 19]

Re: Steam From Exhaust Ports

Bump

 

[KCLOST]

Re: Steam From Exhaust Ports

After a WOT run, steam will exit those ports...

 

[Outrage 19]

Re: Steam From Exhaust Ports

Thanks KCLOST that's when I see it after about 20 or 30 min of running above 3K RPM

 

[thunderbolted]

Re: Steam From Exhaust Ports

dusting off a recently resuscitated 1960 thunderbolt 350,I recently had a water leak around the spark plugs and pulled the powerhead to replace the gasket--also wanted to do the exhaust-port cover gaskets. Nice new bolts, gaskets, meticulous, spotless bench reassembly, and now, it seems I have quite a bit of steam in exhaust??? Don't remember this before, but who knows? Tell-tale steady and warm, no sign of overheating...but I'm afraid of piston or cyl water damage. Any reassurance out there? or preventative recommendations on an all original 50 year old motor?

 

[hkeiner]

Re: Steam From Exhaust Ports

Any reassurance out there?

One way to get better reassurance is to install a temp gauge and water pressure gauge. For myself, I have found these gauges to be much more assuring than my judging if the pee stream or exhaust looks OK.

 

[j_martin]

Re: Steam From Exhaust Ports

You should pull the plugs and peek into the holes once in awhile. A new looking plug and a clean as new piston ususally indicates a little water in the cylinder. If the piston is clean and new looking and the plug isn't, it's too much fuel.

hope it helps
John

 

[nathanglasgow]

Re: Steam From Exhaust Ports

dusting off a recently resuscitated 1960 thunderbolt 350,I recently had a water leak around the spark plugs and pulled the powerhead to replace the gasket--also wanted to do the exhaust-port cover gaskets. Nice new bolts, gaskets, meticulous, spotless bench reassembly, and now, it seems I have quite a bit of steam in exhaust??? Don't remember this before, but who knows? Tell-tale steady and warm, no sign of overheating...but I'm afraid of piston or cyl water damage. Any reassurance out there? or preventative recommendations on an all original 50 year old motor?

Hi,Like yourself i too have a 1961 350 4cylinder that i am resurecting.When i got the motor started after it had sat outside under a tarpaulin for 19 years i can seen no water tell tail.All there is that i can see is an exhaust stub about 3/4 of an inch in diameter near the top of the mid section on its centerline that spits water when the engine is reved.I really have had a good look and can see no other holes on the mid section.Can you tell me where is telltail hole supposed to be.Any replies gratefully accepted.

 

[thunderbolted]

Re: Steam From Exhaust Ports

thanks, John, will check for piston crown steam cleaning, though the plugs are new.-also, is there any easy way or place to install a temp gauge without engine mods? I'd like to keep it all original if possible. From what I can tell, the only places water can enter the exhaust short of a crack somewhere is the exhaust jacket gasket or plate, or the factory hole at the base of the powerhead, which obviously is designed to let water into the exhaust port! Maybe cleaning out the corrosion there is now creating a healthy dose of steam?? if not, if the exhaust water jacket leaks a little into the exhaust will it hurt anything?

cheers, nathan on reviving your '61. I have learned volumes in the last few months about this motor. the pee-hole on mine is, as you face the spark plugs or exhaust port, just under the cowling beneath the powerhead--not on the center section where the exhaust port is. It is on the left side and pees more or less straight down. If you look down at the base of the powerhead, the hole is just inside of where the gasket is. So turn your head upside down and look straight up (skyward) about midway between the cable attachments and the exhaust port.--It's about 3/16ths or so in diameter. Also, try poking a wire up it to get water... Or, does it pee when you flush the motor with the hose? If so, probably replace the impeller pronto. And I wouldn't run it too much until it pees.
cheers, Paul

 

[nathanglasgow]

Re: Steam From Exhaust Ports

Thanks Paul,Yes i can a see small hole exactly where you said it would be.I have tried poking wire up it and the wire will only go up about 1 and a quater inches.Is this the same as yours?Water still does not come.I am running the motor with the lower unit removed and the hose connected to the water tube.Water goes up the tube fine and circulates around the engine fine.It is cooling fine as i can hold my hand on the cylinder head and engine block for as long as i want without getting burnt.I am waiting for a new screw in water pump cover,top plate and impeller being delivered from the USA as these parts are unobtainable in Scotland.Salt crystal build up is not an issue as the motor is fresh water use only from new.I have also put a foot pump to the hole but can not pump much as whatever the hole leads to holds pressure!As the engine appears to cool fine(run at half throttle for 20 mins-Very loud!!) with the hose connect as described above.I figure as it appears to cool okay i will just put lower unit back on with the new parts and run it my test tank(very big wheelie bin) and if it remains cool then i guess its job done.Any replies gratefully accepted.Nathan

 

[Scaaty]

Re: Steam From Exhaust Ports

My Force 125 is a steamer after a run too...been doing it for years..

That said.. when was the last impeller change?

 

[thunderbolted]

Re: Steam From Exhaust Ports

nathan,
The hole goes through the lower cowling (about 1/8 inch thick), through a gasket and into the water jacket casting of the powerhead. An inch and a quarter seems reasonable as that is about where the hole in the casting turns into the main water jacket. So the water enters the engine through the copper tube (from impeller) into the powerhead casting through the same gasket, circulates around the cylinders, the exhaust port cover, and exits--some through a hole into that 3/4 inch exhaust port on the mid-section, and some through that pesky little hole. I just cleaned and replaced the powerhead base gaskets, cylinder cover gasket and exhaust cover gaskets on mine last week, so its all pretty fresh in my memory. I wouldn't rule out corrosion plugging it--even fresh water will fur up aluminum after 50 yrs. I might try working a very thin flexible wire up the hole while pressurizing the water system GENTLY and try to get that hole to start leaking a little. (When I flush my motor with ANY amount of water pressure, that hole immediately starts peeing) Alternatively, pulling the powerhead isn't too big a job and did shed a lot of light for me. cheers, Paul

 

[thunderbolted]

Re: Steam From Exhaust Ports

by the way nathan, I haven't resorted to the hammer and chisel method yet, am currently building an impeller cover removal tool. let you know... and oddly enough, I know for a FACT that this motor sat in a shed from '72 or 3 until '86 was last run, off and on, for a couple of years from '86 to 88, sat under a tarp from 88 until about a month ago, when I inherited it, and it circulates, cools and pees with the best of them...The impeller has NOT BEEN TOUCHED!!! I'm almost scared to disturb it though I have a new one waiting in the wings...so if yours looks oddly good, I'm not surprised-don't make them like they used to. Paul

 

[old-gubbins]

Re: Steam From Exhaust Ports

Good luck with both your Mercs. We have a 30 year old Merc 500, same era.
Now for the thread hijack:
Nathan, I had recently a blocked tell-tale on a 2.5hp Merc, and it did not clear with a foot pump, but it did with an airline.

If you can get at it, apply an airline directly to the telltale outlet on the powerhead. Far more pressure available in an airline. Don't apply it to the tell-tale rubber tube, as you are just likely to burst the tube.

I suppose there is the risk that you could burst a corroded and weakened interior section, but I think it would be better to do that in the workshop than have it fail out on the water. If there is any risk, I expect someone with far more experience than me will warn you.

hth

o-g

 

[thunderbolted]

Re: Steam From Exhaust Ports

Nathan, curious if you ever got water from the telltale? paul

 

[nathanglasgow]

Re: Steam From Exhaust Ports

Nope.Not a drop.Its been poked and prodded and airlined and it made hehaw of a difference.I once had a British Seagull 5hp that had blocked waterways in the head.I turned it upsidedown and poured kettle descaler into the water outlet hole on the underside of the block and left it there for a few days.Cleaned it right out and pumped water fine ever since.I might try this approach if i can be bothered but as the motor seems to cool okay with a garden hose and low water pressure applied up through the water pipe in the mid section when i get the new water pump parts from a company called vintage outboards(been ten days now but the parts have to cross the Atlantic) i will probably just fit them and live without a telltail.Cheers Nathan

 

[nathanglasgow]

Re: Steam From Exhaust Ports

P.S Just wondering how did it go with getting the screw in water pump cover off?Was it a butcher job or did you get it to unscrew.Nathan

 

[nathanglasgow]

Re: Steam From Exhaust Ports

Update.New parts installed,impeller,top plate and water pump cover.After wasting a hour getting the gear shift all in sinc its all back together.Ran it for 20 mins at 1/3rd throttle in gear with prop removed in a large bin of water.Still not a drop from the tell tail but motor did not seize or make any strange noises.Restarts on one pull when warm.The crankcase is hotter than the cylinder head(where the spark plugs go) and the side of the cylinders can be touched for 5secs without getting burnt so im just going to use it like this and see what happens.Can anyone tell me how hot the side of the cylinders are supposed to be just out of curiousity?.Considering the age (1961 350 4cyl) i dont expect it to last long but if i get an hour out of it then im happy!Nathan from Scotland

 

[Yepblaze]

Re: Steam From Exhaust Ports

Is it normal to have steam coming from the exhaust ports under the tell tale. The tell tale has a steady stream of water coming out, I can put my hand in the stream, it’s hot but not scalding. Also from reading past posts I remember some one saying if you can hold your hand on the head for more than 3 sec it’s not running hot. Call me paranoid but I don’t remember steam coming from the exhaust ports before.

Heck yea it's normal.

It's fall, and almost winter.