Leaking exhaust or worse ?

Lads old faithful is playing up again… my 33 hear old 25hp Johnson cut out on me last week and I found out it was because fumes from the exhaust are getting in under the hood and starving the engine of oxygen, I also noticed a lot of staining on the outside of the hood by the gear lever,

It runs fine with the hood off but dies within seconds of putting it back on…. Is there some kind of seal that I can replace where the engine meets the exhaust or could the problem be much more complicated than I think,

Could I have blown a head gasket or something like that…

In anticipation of your kind help I thank you.

Hi mann prob just need to replace the exhaust gasket plate which you could pick up cheap enough (loads on ebay) , I wouldnt bother with a quick fix seal as they dont last long..as for a cracked head gasket the engine would run erratically and there would be lots of white smoke.. I would check the spark plug cable for any signs of damage as when you said that the engine runs fine with the hood off it could be that the cable has been damaged... hope this helps..

John

Hi John

Would you happen to know if the plate replacement is a major job… will I have to remove the motor to get at the part or do I take the prop and upper leg off,

This is one job I have never seen done so I don’t know where to start,

Cheers

Hi John

Would you happen to know if the plate replacement is a major job…
Cheers

It really depends on how good of condition the engine is in if the bolts are rusted and they snap well plenty of wd40 needed and a bit of paitence..if you could post a few pics of the engine and maybe the engine code it would help with doing a step by step ( just to make sure were singing of the same hymm sheet) I am possibly heading towards your part of the world this friday to sunday so pm me your number and Ill see if we can hook up...

Hi John,

Thanks for taking the time man the engine is a 1978 johnson 25Hp seahorse model # 25BAL78C - Serial # B 10757, I gave these numbers to a chap in the USA to order some bolts for the impeller cover and he reckoned it never came up on his list but that could be because it was an export model,
he sent bolts from another Model of that year and they fitted perfectly, the reason for me telling you this is in case you too have a problem finding the exact model,

I did find out that there are 2 types of impeller for that year "78"

the boat is moored in limerick city at the moment so if you did have a little time on your hands while you are here it would be a great help if you could point out where I need to start in taking this apart,

I just got down to take a few snaps before it got dark.. if you look you will see a pencil pointing at a nut thats not in view of the camera... its a locking nut but its loose - could this be part of my problem, would be on the right as you look at the picture, another picture with the pencil on the left of the engine is pointing at a bolt that has a very clean head - as if a nut had just jumped off of it,

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Hi John

Think I found the cause of my problem, that self tapping screw you spoke off has it got different threads at either ends,

I found out why the nut was vibrating - the double threaded bolt it was on had snapped and was just sitting in its hole which probably caused the nut on the other side to vibrate off,

I got kinda depressed thinking of having to strip it all down so I could drill out the rest of the bolt before fitting a new seal - so I said knickers to it and went and got me a bigger and better boat to cheer me up,

I was after this boat for about 2 years and finally it came to me, its an 19ft Orkney with a wicked 40hp lump on the back,
Have to say it did the trick and cheered me up nicely , I think the best thing for me to do with the other engine is give it in to be fixed and serviced then say goodbye to the Lucky ~ B.

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Nice vessel! Well wear!

God bless all who sail in her

love your style so what happens when the car breaks down

Thanks Jim,

I been after a boat like this for a couple of years so when I got a text from a friend of mine to tell me his mate was getting rid of this boat so I jumped on it,

When I went to see it I was amazed to find it well exceeded everything I was expecting - to me and many of my mates the boat alone was worth the price but it got better and better he gave me everything a man would need to go sea fishing, I couldn’t even think of haggling with this Gent as this had to be the best deal I have ever come across in my life,

He was such a nice guy to deal with that I told him if he ever wanted to go out fishing in the boat he should give me a bell and I would gladly give him the keys for as long as he wanted,

Jim I hope to see you in cork harbour some time, I been thinking of going there for some time and now I have the proper tool for the job it wont be long before I take her down for a dip.

Hi John,

Thanks man We will have to wait and see what happens if my transport breaks down - but my dishwasher stopped working a few years ago so I divorced her and moved back to my mothers

The engine on this boat is wicked, it’s such a miser on juice that me and the mate are planning a trip down the estuary “Limerick to Carrigaholt” when the Tope are around,

Well wear with the new boat, fine looking machine