Cut holes in doghouse?

[Buzzsaw420]

I have a 1979 120hp OMC that runs just fine with the doghouse raised but the idle roughens up when I put the doghouse back down. Is it so airtight that it is starving the carb of air? Could really use some help before I use my new 3 1/2 “ hole saw to put a couple vents in the front of it. Thanks in advance, Mark.

 

[GA_Boater]

Turn on your bilge blower which makes air flow though bilge and doghouse. I doubt it's airtight.

Also, look for rub marks inside the doghouse hitting something when it's closed up. If it has any lining, is any loose?

 

[Scott Danforth]

No way to make the doghouse air tight enough to cause it to run bad.

Going to go with something rubbing, shorting out or being pinched, or your motor is afraid of the dark

 

[Buzzsaw420]

Thanks for the replies, I reapolstered the seats and doghouse all new foam and vinyl it’s pretty tight back there, checked for rub and pinch marks there’s lots of room in there. I have not tried running it with the blower on so I’ll give that a go. Thanks again.

 

[Scott Danforth]

Seriously, look to see if the doghouse is touching a wire, especially the spark plug wires

 

[Buzzsaw420]

Going out in the morning I’ll triple check to see if it’s hitting anything under there the last thing I want to do is cut holes in it. Thanks.

 

[matt167]

Well if your exhaust gaskets on the engine block- manifold connection are leaking, then that could be choking the engine with exhaust. It happens on outboards when the base gasket leaks. But if they are bad, you should be able to hear it on an I/O... Don't run it like that if it is, since carbon monoxide would then be settling in the bilge and in your breathable air on the boat

 

[Buzzsaw420]

Thanks Matt, I do have a very small drip in there that must be coming from the manifold but it wasn’t enough that I was going to do it this year.

 

[hugh g]

Check your flame arrestor which can clog up with crappage over time. If it's dirty, clean it.

 

[Buzzsaw420]

Thanks hugh g , I tried it with the flame arrester off and it started to chug as soon as the doghouse went back down. I will check for any blockage.

 

[Buzzsaw420]

Hi guys I have just noticed that I am missing the flame arrester gasket that goes between the flame arrester and carb would this have anything to do with it chugging when the doghouse goes down? Thanks again, Mark.

 

[PITBoat]

Are the vents on the sides of the boat that communicate with that area open?

Assume for argument it's air starved when you shut the lid. The reaction wouldn't be immediate like that, if that's what you're saying.

Gasket or no wouldn't make any difference.

 

[Scott Danforth]

Hi guys I have just noticed that I am missing the flame arrester gasket that goes between the flame arrester and carb would this have anything to do with it chugging when the doghouse goes down? Thanks again, Mark.

no

 

[Buzzsaw420]

Yes the back vents are clear and open. As soon as the doghouse goes down you notice the idle slow down

 

[Scott Danforth]

Yes the back vents are clear and open. As soon as the doghouse goes down you notice the idle slow down

is it really slowing down, or just getting quieter?

as stated, closing the doghouse would not effect the idle of a boat, especially as quickly as you describe unless you are moving wires with questionable connections. even if the box was 100% air tight (as in compression gaskets, etc), it would be about 5-10 minutes before the air in the box was depleted enough to affect idle.

 

[Buzzsaw420]

It takes about 20 seconds as soon as I close it before it wants to start chugging and stall

 

[flashback]

Well if your set on trying out the new hole saw, go ahead and do one hole and install an inspection plate on it. if you find it doesn't solve your problem you will at least have an access hole for a fire extinguisher so no harm done..

 

[Buzzsaw420]

Thanks flashback I think I’ve tried everything else and after recovering the seats and doghouse I think it’s just too airtight in there. I’m going to put a hole in it and see what happens. Thanks to everyone for your help. I will report back after I Swiss cheese the doghouse. Cheers, Mark.

 

[Buzzsaw420]

I didn’t know if I should start a new thread this is still sort of the same. The exhaust leak is coming from the front of the exhaust manifold at the heat exchanger tube, I can’t find a good picture in my service manual or parts list where the tube goes in. Mine looks like it was previously gooped on I’ll try to post a photo. My question is can I just regoop with marine-Tex gray if I can’t find this part. Thanks again.

 

[GA_Boater]

Keep this thread going.

The other end of the tube must go to the choke to heat the bimetalic spring that opens the choke. How is your choke working?