De-carb question.

[steviecops]

Are there any visible signs which would tell me if a de-carb has cleaned my engine properly?<br /><br />I ran a can of OMC engine tuner through my carbs at a slightly high idle speed. The gave the carbs a good squirt each and shut the engine down to let it soak in. After 3 hours, I started the engine and ran it again for about 20 minutes.<br /><br />I was expecting lots of smoke and rubish to come out, but the smoke wasn't that bad, and I only got a little bit of black staining around the exhaust relief ports. The smoke that did come out smelt "nice", so I know that something was happening in there.<br /><br />The reason I ask is that my engine seems to be running cool, (I think the stat has been removed or seized), and I thought a cool running engine got carboned up pretty bad. Should I do another de-carb, or does it sound like I cleaned my engine successfully?<br /><br />Thanks<br />Steve

 

[rickdb1boat]

Re: De-carb question.

Sounds like you got it pretty good to me. You might pull a plug and peer in there with a light to see how the piston tops look. Why do you think it's running cool? Have you checked the temp. of the engine yet? If you think the stat is bad, remove it and replace it for proper warm up and temp control.

 

[steviecops]

Re: De-carb question.

Thanks Rick<br />I think my engine is runing cool because it hasn't idled great since I've had it, and I've done all the other jobs that should have smoothed the idle out. I cleaned and rebuilt the carbs, replaced all fuel lines, rebuilt fuel pump and filter, changed plugs, replaced a suspect looking ignition coil, did the de-carb and did a link and synch.<br /><br />After running the engine for 10 - 15 minutes, I can keep my hand on the head for as long as I want and it doesn't get more than warm to the touch. It's a 1980 johnson 55.<br /><br />I will put a new thermostat in after the summer, as I just know that I'm going to have problems getting the head cover bolts out and I don't want to be too long without a boat during the Bass season!<br /><br />Thanks again<br />Steve

 

[BillP]

Re: De-carb question.

Your motor probably wasn't dirty. It takes a lot of hrs to build up major crud. It doesn't happen in 100-200 hrs unless the motor is real, real sick. Did I say it takes a long time?

 

[ob15]

Re: De-carb question.

steviecops<br /><br />You may be surprised how easy the head cover bolts come out. I just did my 80 rude 50 & it was pretty easy. After reaading previous posts, most of the input from the experts was that it is not good to run the motors too cool or too hot. You may want to change the t-stat.

 

[rickdb1boat]

Re: De-carb question.

I agree with Dave. replace the t-stat now. Your motor will run better and it's a nessesary part of the system. Should be no big deal. Give it a try, anyway. If it's too tough, run it until you can get to it.

 

[steviecops]

Re: De-carb question.

Dave and Rick<br />Thanks for the advice, you have almost tempted me to start the job now! I know I should get straight to it, but if things don't go well, I could end up having to remove the powerhead or some other drastic measure to get the bolts out, and being a beginner, it would put my boat out of action for some weeks!<br /><br />I think I'll give all the bolts a good soak and a little try to see if there is any movement. I might be lucky like Dave and they may all move, if so, I'll do the job there and then. If some are seized though, I'd be better off waiting. One thing I learnt from my frozen lower unit bolts is that patience is everything!<br /><br />Thanks again<br />Steve

 

[ob15]

Re: De-carb question.

You could also try each bolt to see if it will loosen (just a little bit without removing them). If they do chage the t-stat. If not keep soaking them until you can get them all loosen then change it. It only takes a few hours. Getting the pressure relief spring back in was a little tricky and getting the old gasket material off the surfaces was a little time consuming. Other than that it was pretty easy. Total time should be no more than 2 hours.

 

[steviecops]

Re: De-carb question.

Thanks dave<br />I had a little play with the head cover bolts today for about an hour. Not as bad as I thought it would be. <br /><br />Out of 14 bolts, 8 undid really easy, and six were seized. Out of the six seized bolts, I managed to get some movement back and forth on three of them after a lot of soaking with Plus Gas. The other three I can't get to until I move the cowling out of the way and remove the bottom ignition coil. (I might have known that the seized bolts would be the ones on the bottom that you can't get to! )<br /><br />Anyway I've tightened everything back up for now and will continue to soak the three frozen bolts for a while longer before I pull it all apart. Any tips on getting that cowling out of the way? I removed the two small bolts at the front on the lower cowling, and the little front plate, but my manual doesn't show which other bolts I have to remove.

 

[BillP]

Re: De-carb question.

Use a heat gun on the bolts to help loosen them up. Do several hot/cold cycles for best results. Penetrating oil won't get in deep enough if they are seized badly. Sometimes the slight back and forth movement of bolts means they are breaking, instead of loosening.

 

[ob15]

Re: De-carb question.

Glad to hear you got some of the bolts loose. Be patient with the rest & I bet you get them.

 

[steviecops]

Re: De-carb question.

Thanks guys<br />Is it O.K to use heat near the head and head cover? The cover looks pretty thin and flimsy, is it possible I could make it or the head warped by applying heat there?

 

[DJ]

Re: De-carb question.

steviecops,<br /><br />It's OK to use the heat. Just make sure you concentrate it on the bolt heads and not surrounding areas.

 

[steviecops]

Re: De-carb question.

Thanks DJ<br />I only have the use of Butane, better than nothing I suppose, but will that get the bolts hot enough?

 

[DJ]

Re: De-carb question.

Should be fine.<br /><br />The trick is to get them hot, let them cool and repeat several times.

 

[steviecops]

Re: De-carb question.

O.K DJ, will do.<br /><br />Thanks a lot.<br /><br />Steve

 

[SCO]

Re: De-carb question.

Just want to throw this thought out. I have a new butane lighter that is a mini torch. You can also get small cheap mini butane torchs too. Seems perfect for heating a single bolt. Q: Would you want to heat up the bolt for a few minutes and then for a few seconds sink out the heat of the bolt to allow it to contract while the threads remain hot and expanded? I have never done this procedure and am contemplating removing head bolts on my motor.

 

[wayne h]

Re: De-carb question.

heat the bolts up and soak them with your penatrating oil to cool them. doing this will pull the oil into the threads. i dont know what u are using for penatrating oil but i only use PB BLASTER i have not years and it works great.. just take your time and good luck

 

[BillP]

Re: De-carb question.

Be very careful using any type torch around aluminum. It will puddle faster than you can blink an eye. If you don't have a heat gun a safer bet is your wife's hair drier. It won't melt aluminum and will give plenty of heat.

 

[G DANE]

Re: De-carb question.

Not to be negtive, I dont think the heat from a hairdryer will do any good. My experience is best result is heating bolts up to redhot by welding will break them loose. <br /><br />Drill a hole in a piece of metal sheet the size of bolt head, use a small torch or even a cheap pencil torch, and heat it all you can. Watch the surrounding alloy carefull.The heat expansion will squeeze what sticks the bolt. When cooled down all the way and soaked, make next attempt.