head gasket?

[The-Machinist]

My '71 johns. 40hp electramatic seems to blow quite a bit of steam when running, replaced water pump, still seems to be running a little hot. I can hold my hand on the head no more than 2 seconds before having to pull it away. the water coming out of the idle relief port is hot, but not hot enough to scald. the steam on the other hand is scalding hot, and coming fron the same place. does this sound like a head gasket? how can I test to be perfectly sure if its the head gasket or not?

 

[Solittle]

Re: head gasket?

Start with a compression check and post the results back here? What do the plugs look like? Have you replace the t-stats?

 

[F_R]

Re: head gasket?

Yeah, how about the thermostat? Have you checked it? Did you put in a complete new water pump?

 

[The-Machinist]

Re: head gasket?

I replaced only the impeller, but every thing else in the pump assembly looked perfect. compression 102, top 104,bottom. plugs look ok, kinda dark but not wet or oily. no new thermotsat till tommorow, but I removed the current one and still felt hot. Also, when I remeved the lower unit the shift controll wires were pretty well crispy and insulation burned and broken.

 

[F_R]

Re: head gasket?

You gotta deal with those wires. If they short circuit together, it will bust something like the drive shaft.

 

[F_R]

Re: head gasket?

Not to mention that if the wires are exposed to water, they will quickly eat themselves in two from electrolysis.

 

[The-Machinist]

Re: head gasket?

The wires have been replaced now, the omc part was over $150 so I made my own with very high temp low voltage wire and sealed the heck out of it. Now if I can only figure out if it needs a head gasket

 

[F_R]

Re: head gasket?

If it got hot enough to burn the wires, probably needs a new head gasket and exhaust cover gaskets. Any leak that allows exhaust to blow into the cooling system will kill the pumping.

Is the white plastic check valve in/below the thermostat housing? Have the water tubes been swapped? The one with the spray hole goes in the water "up" position. The other one is water return. Are the water tube grommets in good shape? We can keep guessing, but you have the advantage of eyes-on evaluation.

 

[The-Machinist]

Re: head gasket?

I have no white plastic check valve. should it be directly below the t-stat?

 

[F_R]

Re: head gasket?

The thermostat sits in a black plastic housing with a hole in the bottom. Under that is a white plastic check valve with a spring under it. Actually it is really a relief valve, opening under pressure as determined by the spring. If it isn't in there, you are in recirculation mode all the time. See the parts list at
http://epc.brp.com/default.aspx?brands=ej&lang=E

 

[The-Machinist]

Re: head gasket?

my t-stat sits high up top on the rear of the head in an aluminum housing held by 3 screws. there is a hole that goes straight down and one that goes off in an angle towards the head. Is this the same one you speak of?

 

[F_R]

Re: head gasket?

Yes, isn't there a black plastic insert in the head where the thremostat sits? The relief valve goes below that, up against the straight down hole.

 

[tashasdaddy]

Re: head gasket?

saw your other post, for the port head, try tcoutboard.com and hornes salvage st.petersburg fl oem # head 317850, gasket 318334 at ishopmarine.com

 

[The-Machinist]

Re: head gasket?

Ok,today i put in a new whole pump asembly, changed the head gasket, and replaced the t-stat. there is no plastic in the head as far as i can tell. So far it ran about 20 min. at idle, and half throttle. feels much cooler, can keep my hand on head 10-15 sec. dont worry, I had the boat backed in to my pond for half throttle test(any more than half it sucks air to the prop and revs jump up). I am taking it to the river tommorow and going upstream,and taking my trusty 2.5 merc for back up. will let you know how it goes.

 

[F_R]

Re: head gasket?

Did you look at the exploded view on the BRP site? I'm telling you that thing is supposed to be in there. It opens when the thermostat is closed to direct the water back to the pump, where it keeps recirculating till it warms up enough to open the thermostat. When the thermostat opens, there is less water pressure and the relief valve does not open to recirculate the water.

If the valve is not in there, the water will recirculate all the time and it will run hotter.

 

[The-Machinist]

Re: head gasket?

well, I feel like an ***. Imported's last post was eating at me so I went out to the shop and pulled the t-stat cover again and did some digging around. Well what do i find? The fabled piece of black plastic that holds the check valve. I will never doubt your wisdom again. The piece is stained brown from use, I looked in, didnt see any black, and assumed you were thinking of the wrong engine. A thousand apologys. I was not able to pull up the link because this rock I try to pass of as a computer would not let me, so I forged on in ignorance. I now know that I need a check valve, but I have no idea where to find one. If any one has a part # or knows where to find one I would be very greatful

Ps listen to these guys, they really know thier s--t

 

[The-Machinist]

Re: head gasket?

Oh yeah, just in case the model is: RKL-30 D seiral :J2901427

 

[F_R]

Re: head gasket?

Thanks for the model number. I knew you don't have a 1971 just by the fact that you have a thermostat. '71s don't have them. You have a 1968.

The parts listed in decending order from top down are:
303085 cover
305196 gasket
378065 thermostat
305266 thermostat housing
305195 seal, thermostat housing
305197 valve, pressure control
305199 spring, control valve

The parts were used in 35-40 hp Johnson and Evinrude motors for about 12 years. Try your local Johnson/Evinrude dealer or on-line at ishopmarine.com or www.sea-way.com/

 

[The-Machinist]

Re: head gasket?

Well, I sure could use some more advice. I took the old johnson down to the pond and let it run for over 30 min. at half throttle and less, she ran perfect. (Thanks for the advice with the check valve F R, she runs nice and cool now) Well, i took it down to the river and took off up stream. Right away I noticed it wasnt running right, so I opened the little door on the front and the cowling is full of exhaust. I left the door open and it ran great. I almost got on plane when it jumped out of gear at full throttle. Scared the he!! out of me, so I shut it down, then started it back up and it runs perfect so I dropped it in gear and it just kills the motor. Long story short my shift wires melted and luckly disengaged 1st instead of engageing reverse. Motor runs fine but I need to know where to start looking for my exhaust leak, and why do my shift wires keep getting melted when my motor runs quite cool now?
Any advice would be very helpful, Im losing my faith in electric shift