40+ Crankcase gets very hot!

[John1952]

Sorry guys me again , I have managed to get my new edition running well, the thing I am worried about is;
the crankcase get very hot when running, It has a good water flow!
Unlike my other Gulls, this one, for some reason, gets quite hot!
Any help with this problem would be great, I have looked through Q/A and am unable to find anything relevant.
Many thanks; John.

[Waggles]

Could be the waterways are partially blocked so although you have a good flow the water is not getting to all areas of the block perhaps? Suggest a damn good backflushing!

If you do mean the crankcase and not the barrel only other thing I can think of is that after years of standing the bearings could be a bit dry. Try removing carby and introducing some oil into the crankcase and getting it to run everywhere by moving motor around / inverting etc.

Final thought, what mixture are you using? is it correct for the carb? if it is running weak it is likely to run hot.

[John1952]

Thank you for your reply Waggles, yes I did mean the crank case; not the barrel!

Waterflow is good, I now have her in bits so I will do as you suggest and get some 3in1 inside her.

I run all my engines on 10/1 a bit smokey, but they are all well lubricated.

The carb is a villiers mk2, I can't check the needle, I am unable to get the screw out from the top of the slide! Any Ideas?
once more, Many thank's, John.

[phil]

Try covering it with lacquer thinner or acetone in a jar, let it soak overnight or two. Should loosen it up.

[phil]

Lid tight on jar, if you want any left, for soaking other fuel gummed up parts.

[Waggles]

Yep, try Phil's trick, maybe a little warmth might help too ( I mean boiling water not welding torch!! )

You definitely need to check the needle as if it HAS been converted to 25:1 you will be running too lean using a 10:1 mix. True it will be well lubricated but once the oil has condensed out there is less petrol left for a given volume of fuel / air and hence a weak mixture. Whether you would then want to convert it back to 10:1 is obviously up to you, a lot would agree with 10:1 being better ( the eco crowd not being among them, personally I love the smell of two stroke in the morning )

By all means use 3 in 1 to begin the crankcase lubrication but I would also go on to splurge ( a technical term ) a little neat two stroke in there as well, if the motor is in bits you are trying to make sure both main bearings are well lubricated, the thicker 2 stroke oil will also help seal the bearings and hence the crankcase and avoid air leaking past them which is another cause of weak mixture in motors that have been left a long time.

[John1952]

Thank's Phil and Waggles,
As I said, The carb is a villiers mk2, I can't check the needle, I am unable to get the screw out from the top of the slide!
Any Ideas?
Waggles you say that, (I definitely need to check the needle as if it HAS been converted to 25:1 I will be running too lean using a 10:1 mix. True it will be well lubricated but once the oil has condensed out there is less petrol left for a given volume of fuel / air and hence a weak mixture)
Maybe I will try running it on 25/1 and see how it runs!!

[Waggles]

The idea of using warmth and acetone etc was to get the stubborn screw loose so you can check the needle.

You could mix up a small amount of 25:1 to try, if it hasn't been converted I would expect it to start but probably 4 stroke all over the place and get progressively harder to run as it warms up until finally fouling the plug. Be aware though that earlier engines should not be run on 25:1 anyway due to bearing differences so checking the needle is the safer bet.

You could probably find a cheap carby to whip the slide out of perhaps if it really won't come out.

[Charles uk]

Hot crankcases are quite unusual in Seagulls, ( hot is almost too hot to touch) & is caused by the main bearings or big end running very tight, often caused by distortion in the crank or the crankcase.

Both of these would require a full strip down if the motor is important to you, is there any evidence of the motor being dropped on it's crankcase or the flywheel being removed by a giant squid?

[John1952]

Thank's Waggles and Charles uk,
I have managed to get the screw out now and it is numbered 3 so now at least I know it is 10/1 mix
As far as the top of the crank case getting hot, (unlike my other gulls) when she has been running in my bin for say, 10 mins, I cannot keep my hand on the crankcase for more than 5 seconds,(hot) so I guess like you say Charles, a strip down is in order!
I have just taken the block off again and am soaking it in 2stroke oil overnight, fingers crossed Charles; I see no sign of damage to the crank or shaft!
Thanks for all your help and advice guys, John.

[Waggles]

... and don't forget to keep it away from giant squid ......

[John1952]

Just to let you know I soaked her in 2 stroke oil overnight, just put her back together again and ran for 10 mins. She did get quite warm, good water flow! but not as hot as yesterday!

Tested another 40+ for 10 mins also, good water flow, and found that there was not a lot of difference. Both got quite warm, Is that unusual?

Maybe the one I had the problem with, was a little hotter, but not that much.
So I think soaking it overnight helped I guess! (Thanks Waggles) Saved a strip down

[Waggles]

Glad to help.

Gotta be honest and say I have never actually felt the temp of my 40's crankcase while running ( I'm too stupid and would probably just get tangled in the flywheel ) and once stopped I am usually too busy trying to remember to avoid the exhaust ( now that IS hot, don't ask me how I know )

Not going to the boat this weekend but will try to remember next weekend and see how hot mine gets bearing in mind she has to run around 3/4 throttle for 5 - 10 mins to get me to my mooring, sometimes flat out if the weather is f5-6 'Noserlies' so should be a good test rather than the good old wheely bin.

[Charles uk]

I have a hand held infra red thermometer that I check main bearing temps when I first start testing my race motors, just to see if I'm over doing it on the main bearing loading front.

[atoyot]

....As far as the top of the crank case getting hot, (unlike my other gulls) when she has been running in my bin for say, 10 mins, I cannot keep my hand on the crankcase for more than 5 seconds....

Hi, John.

For what it's worth, if you're running your engine in a bin, tank, or etc. and especially if the prop is still attached, the impellor is going to be circulating very bubbly water about the cylinder head which isn't as efficient at cooling as normal water would be. You probably know all that, being a collector; why your other engines aren't so affected by this I couldn't say except that it might possibly suggest that the one in question is on the edge of cooling efficiency due to scale or rust inside that isn't coming out with just a flush.

Just an idea; would love to hear how it all works out.



-Ted