383535 vs 311932

[jitterbug127]

The spark plug socket is cross threaded on a new motor I just bought a 1969 25 hp Evinrude. I took the cylinder head off to buy a sav a thread to put into it. Got on eBay looked around and actually found a brand new old stock omc cylinder head for a 20 hp part number 311932. The part was actually at a warehouse up the road from me. They look identical, but I wanted to make sure they were innerchangable before I ruined a nice running motor. I know this part wouldn’t be one to install the wrong one on. If it doesn’t work I’ll keep this for a future day and order a helocoil kit.

Thanks in advance!

 

[Black58]

The socket on the plug jammed up or the plug cross threaded in the head?

 

[jitterbug127]

The cylinder headed is cross thread.

I don’t have the parts side by side but I can from
More pictures it won’t fit. Exciting to know there are new old stock of omc parts near me. I’d that alone is with the knowledge

 

[jitterbug127]

The part where the spark plug goes in won’t hold a spark plug anymore. I’m not exactly sure what to call it.

 

[jitterbug127]

I'm going to use a helicoil on the blue cylinder head assembly above.

My question is...Should I use gasket sealer? The new gasket i ordered says specifically "Do not use Sealer". I assume this is what I should do, but wanted some more assurance. Thanks in advance! Rob

 

[tphoyt]

Sorry I don’t have an answer for the head.
There could be slight differences in bore diameter and the depth of the head.
No sealant need for the head gasket.

 

[jitterbug127]

I don't know for 100% sure either. The brand new cylinder head assembly was $35 still in an OMC box like 20 minutes from my house, and they take returns. It seemed like it would be worth a shot. I just picked it up tonight on my way to work. I am going to compare the new and old part side by side to know if they're the exact same. bolt patterns match and its same head gasket for both. From pictures it looks like the 25 has a little less metal inside where the cylinders meet the assembly than the 20 does, but only looking at them in person will be able to really tell.

 

[Chuck Gibson]

I had a few spark plugs blow out of a Ford 4.6 V-8 a few years ago. (not all at the same time)... I found that helicoils failed after a short period of time. After hitting some F150 forums I learned of a system called "Timesert". I don't know if they would have the size you need for your spark plugs, but if they do you would be gauranteed success. Talk to a few automotive repair shops in your area. I'm sure they would have Timesert systems or something comparable. Chevrolets also had simular problems with plugs snapping off. Systems were made to repair those threads as well. The inserts they use actually go through the head and mushroom out on the back side making it impossable for them to leak...
Good luck!

 

[jitterbug127]

I will do that! Love learning about different options.

The correct part is $70 On eBay so I’m thinking that might be my best option.

 

[jitterbug127]

Part on right is 20 hp (my new part) part on left is 25 (my old part). This replacement won’t work. Too good to be true. I really tried!

 

[Chuck Gibson]

Part on right is 20 hp (my new part) part on left is 25 (my old part). This replacement won’t work. Too good to be true. I really tried!

They really look simular. What is the differance? Bolt pattern?

 

[saltchuckmatt]

Did you try to chase the thread out using a tap with lots of oil spinning it back and forth?

Because if you did, and it didn't work then I usually, if the head is actually off, have my welders spot shot some aluminum in there and then I drill and tap it out.

Easy peasy.

 

[jitterbug127]

Did you try to chase the thread out using a tap with lots of oil spinning it back and forth?

Because if you did, and it didn't work then I usually, if the head is actually off, have my welders spot shot some aluminum in there and then I drill and tap it out.

Easy peasy.

I have not tired to do this yet. I do know the spark plug will just fall out of the hole right now.

I do have the head off. It came off really smooth. Ill compare both my parts side by side when i get home. if that doesnt work ill try your method. I like it better than the helocoil TBH.

 

[jitterbug127]

They really look simular. What is the differance? Bolt pattern?

I think the pictures look different, but it might just be angles. I get off at 11 EST tonight. Ill check my new part compared to my old. if they both look same I'm good to go. Bolt patterns are exact same.

 

[jitterbug127]

Here are my 2 parts. I tried to capture the difference as you can see in the picture.

 

[saltchuckmatt]

Either measure everything and I mean everything or chase out the threads. Not sure why you even purchased one.

Next, weld shop and re-thread.

Send the head back as defective.

 

[jitterbug127]

Either measure everything and I mean everything or chase out the threads. Not sure why you even purchased one.

Next, weld shop and re-thread.

Send the head back as defective.

I’m not sure either. Cheapness and the thrill to experiment.

 

[jitterbug127]

It’s up the street wirh free returns. Seemed with a shot.

 

[saltchuckmatt]

"either"

Don't assume anything.

 

[jitterbug127]

Part is getting returned tomorrow.