Evinrude Fastwin 18 HP 15032 Leaking Around Exhaust

[fleetwin]

I’m not sure I understand just where the leaks are here….Sounds as if you are saying that water is squirting out around some center screws in the exhaust cover…. Like Dave says, my first thought would be that the screws are bottoming out and not actually tightening the cover. Dave’s washer idea sounds like a good test.
I am very concerned about this issue though. You have just done a great deal of work to this engine, exhaust water leaks that might be getting back into the powerhead could ruin it…
Putting washers under those screws might only just “mask the real issues” here. The washers might stop the external leaks, but internal leaks might still be occurring. I know the thought of pulling that powerhead off and removing those covers again seems like a horror, but you sure don’t want that freshly rebuilt powerhead getting slowly ruined again….
I realize you are not using the original fasteners, I’m assuming your new hardware is threaded all the way up…

[fleetwin]

PS Perhaps you can post a video of the engine running and leaking… Was this a fresh or salt water engine? Is the outer cover in good shape? Perhaps it is damaged, corroed/eroded….How about the inner SS cover?

[sydinnj]

When chasing the threads are you using a bottoming tap?

[Crowsbeak]

Fleetwin-unfortunately I do not have a video of that side of the motor when it was running and I have fogged the cylinders to try to eliminate it seizing up again until I can chase down the cause. The spark plugs were definitely wet when I pulled them to fog the cylinders. You are correct in your understanding that the water was leaking around all 4 of the center exhaust cover bolts, not squirting per se but a constant drizzle. I will need to pull the power head to access the lower two center bolts as it is too tight to work on it in the exhaust leg so pulling the whole exhaust cover is still definitely on the table. I agree I have too much work into it and really want to eliminate the root cause. It is a freshwater motor and everything looked ok on reassembly, no saltwater corrosion nor any pitting or pinholes that I could see on either the outer or stainless inner cover and everything cleaned up real well. I blew out all the water passages to make sure they were clear prior to reassembling the block. There was a lot of carbon buildup on the exhaust side which was removed during cleanup. I assumed the seize up was caused by a lower seal failure as has been discussed in numerous posts but it may have occurred from an exhaust leak. perhaps the carbon buildup caused everything to warp a little as suggested and likely led to seized bolts.

sydinnj I did not use a bottom tap just a cheap harbor freight tap kit but did blow all the holes out with air and carb cleaner but I get your point that perhaps some debris is stopping the bolts from reaching full depth.

My plan is to pull power head, pull and dress outer exhaust cover, and reinstall with washers under the bolt heads to eliminate bottoming out of the bolts. Cleaning threads and resealing will also occur. I will post back results but it might be a few days.

Thank you all for help and ideas.

Jeff

1954 Evinrude 7.5 HP
1954 Evinrude 15 HP
1954 Gale 12 HP
1955 Johnson 10 HP
1956 Johnson 10 HP
1956 Gale 12 HP
1956 Evinrude 5.5 HP
1958 Johnson 7.5
1960 Evinrude 18 HP
1973 Johnson 6 HP

[fleetwin]

OK, I’m assuming the screws you are referring to are the screws that separate the water jacket from the exhaust chamber. I made the mistake of buying a set of taps from HF, ended up tossing them out, the pitch was off slightly. I would go to Lowes/Napa/car parts place and buy a few decent bottoming taps. That HF tap might have messed up your threads to the point where the screws won’t thread in properly. Yes, I realize this was my experience, perhaps the taps you bought are OK, but I would check it out with a good quality tap, you don’t have to buy a whole set. You may want to consider ordering the proper OEM screws also. Once the threads are cleaned out, I would thread each screw into a hole to make sure it goes in deep enough to clamp the covers properly. I would skip the washers, the screws should be able to seal on their own…If not, there is something else wrong.
Once the covers are properly installed, you might consider installing the powerhead without the lower pan in place…Order a few base gaskets, use a base gasket with no sealer to ease clean up when the powerhead is pulled off again and the pan reinstalled. I would use the gasket sealer on both exhaust cover gaskets, and on the threads of the screws also.
Once you have run the engine to confirm there are no leaks, retorque the screws before pulling the powerhead and reinstalling the pan…
Yes, I know I’m advising alot here, I just want this issue resolved properly, and don’t want your powerhead rebuild damaged.

[Crowsbeak]

Thank you Fleetwin for the detailed advice. I will get to work on getting a couple better quality taps, some oem bolts and a couple of new exhaust and base gaskets.

I’ll report back on my efforts.

1954 Evinrude 7.5 HP
1954 Evinrude 15 HP
1954 Gale 12 HP
1955 Johnson 10 HP
1956 Johnson 10 HP
1956 Gale 12 HP
1956 Evinrude 5.5 HP
1958 Johnson 7.5
1960 Evinrude 18 HP
1973 Johnson 6 HP

[Crowsbeak]

I want to report back and close the loop on this. pulled powerhead, pulled lower pan, then I removed the exhaust covers and amazingly was able to salvage both gaskets. I dressed the exhaust cover, re-cleaned the threads with a Vermont American bottom tap. I confirmed all bolts would thread in deep enough to tighten the cover/gasket/stainless baffle/gasket. Applied gasket to sealer to both gaskets and all bolt threads reassembled. Bolted powerhead back on leg, confirmed torque on all exhaust bolts and head bolts then barrel tested.

Results: no leakage around exhaust cover found!! Pulled spark plugs and they were not wet! Thank you all for the great advice and your help.

Now for my next question: do you think I should lake test before pulling power head and installing the bottom pan again? I only used gear lube on the exhaust leg gaskets and it was a bit wet around the interface? Will that area leaking a little affect anything or should I put pan back on, seal gaskets and then lake test?

Also, what is the recommended method for breaking in the new rings? So far it has only run a total of about 10 minutes in a barrel between the two barrel tests, so speed was naturally at idle speed.

Thanks again,

Jeff

1954 Evinrude 7.5 HP
1954 Evinrude 15 HP
1954 Gale 12 HP
1955 Johnson 10 HP
1956 Johnson 10 HP
1956 Gale 12 HP
1956 Evinrude 5.5 HP
1958 Johnson 7.5
1960 Evinrude 18 HP
1973 Johnson 6 HP

[fleetwin]

Well, if you have luck like mine, you should lake test first. Then you can retorque the exhaust cover bolts before reinstalling the lower pan. I would replace the exhaust housing gasket, using sealer on the gasket and screw threads….
Glad the exhaust cover leak is resolved…

[Crowsbeak]

Thanks Fleetwin. I am hoping to get it in the water this weekend. I will keep pan off until I confirm no leaks.

I have an extra exhaust housing gasket so I will do as you recommend. When I hopefully reinstall the pan after hitting the lake. Any tips on seating the new rings?

1954 Evinrude 7.5 HP
1954 Evinrude 15 HP
1954 Gale 12 HP
1955 Johnson 10 HP
1956 Johnson 10 HP
1956 Gale 12 HP
1956 Evinrude 5.5 HP
1958 Johnson 7.5
1960 Evinrude 18 HP
1973 Johnson 6 HP

[fleetwin]

Well, I would add some extra oil to the mix for sure. Then run the engine at many different throttle settings, just for a minute or so at a time. Accelerate from idle to WOT, let it come up to speed, then back it off to an RPM setting where it is planing the boat but not struggling/straining….

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