checking exhaust manifold

[Hawki]

What is the best way to check my OMC 2.3 Liter ford cobra exhaust manifold for blockage? I'm sorting out a overheating problem, I'm seperating my lower unit as we speak to check that area and have replaced the water pump impeller and already has a new cir pump.

 

[Speak]

Re: checking exhaust manifold

Hi Hawki, you dont have to separate the drive to replace the impeller. Its under the cover on top of the drive. 3 screws for the cover and 3 for the housing, very easy.
before you do this have you checked to see if you have good water flow from the impeller at the thermostat housing hose?

 

[Speak]

Re: checking exhaust manifold

i see you have another thread going----disregard my previous post. As for the manifold, remove the manifold and look in side and see how much build up you have inside. Also check the flapper in the exhaust pipe is still there and not blocking the flow as well. take the riser elbow off and look down.

 

[Hawki]

Re: checking exhaust manifold

I'm in the process in taking manifold off and removing the exhaust while I have the drive off. In a lake water test I had a good flow from the raw water pump but had alot of bubbles coming out of the small rubber hose hole, it lead me to believe i had a problem in the hose that is in the lower unit. I thank you for your input because as you know every little help helps guide and solve the problem. Thanks again I'll post when I get my results from separating the lower unit and removing the manifold and exhaust. I do believe I have a flapper problem though. Thanks again, Later

 

[jerryjerry05]

Re: checking exhaust manifold

Ever been in salt water?
Sometimes the inside of the manifold can get clogged.
This is how I test for flow.

1- 5 gal bucket.
Hose with good pressure.
Remove the manifold.Inspect the holes on the end for blockage.
Then time how long it takes to fill the bucket with the hose.
Then set the manifold up so it drains into the bucket.
Hook the hose up to the manifold and turn on the water.Time it and if it takes longer it's clogged.
The inside of the drive if it's been overheated the rubber gromets on the water tube can melt and mess with water flow.
You can see the gromets and tube from the front of the drive without taking it apart.
The exhaust has a flapper it can break free and clog the exhaust and maybe cause over heating(not very likely).
That can also mess with shifting if it comes loose.

 

[Hawki]

Re: checking exhaust manifold

Good info. Never been in salt water got some water coming out of manifold at the petcock drain. When you say you can see the gromets and tube and tube from the front , you mean with it partly separated right ? This does help thanks.

 

[jerryjerry05]

Re: checking exhaust manifold

With the drive off.
Look past the shift rod(flashlight) and you should be able to see the tube and the rubber grommets.
Any melting??? You'll need to seperate and replace.

 

[Hawki]

Re: checking exhaust manifold

yes, melted, where do you get the grommets and do you their omc part numbers. Trying to maintain a omc part number list on my repairs. That worked well only had to seperate about 3in . Thanks again

 

[Lou C]

Re: checking exhaust manifold

Evinrude Parts - OMC - Mercruiser Parts - Boats - Crowley Marine
Or, if you want to find a local source any Evinrude dealer can order OE OMC Cobra parts.

 

[jerryjerry05]

Re: checking exhaust manifold

0911715 GUIDE, Water tube 0911705 SEAL, Water tube
You'll need 2 seals and 1 guide.
Any Johnson/Evinrude dealer should be able to get the parts.

 

[Lou C]

Re: checking exhaust manifold



Be careful trying to get the upper and lower gear units apart. They can be stuck on real tight. I posted this pic in a few other threads but after removing the bolts that hold them together (2 on each side, and 2 by the rear anode) and turning the shift rod sideways so that the upper can lift off, some people pry the units apart with wedges and large screwdrivers. I used a couple of bolts + nuts in the lower mounting bosses and a piece of all thread and nuts to take the place of the trim rod ram. I put one scissors jack under the front 2 bolts and one under each end of the all thread. Jack each one up evenly and it will pop loose easily with no stress, prying or cursing.

 

[Hawki]

Re: checking exhaust manifold

Lou c, nice already have the engine stand, this will work great, thanks for sharing. Let you know later.