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720 with repower getting hot

Printed From: Unofficial Allis
Category: Allis Chalmers
Forum Name: Garden Tractors
Forum Description: A great place to discuss the Simplicity and Allis Chalmers Garden Models
URL: https://www.allischalmers.com/forum/forum_posts.asp?TID=127206
Printed Date: 06 Jun 2024 at 12:33pm
Software Version: Web Wiz Forums 11.10 - http://www.webwizforums.com


Topic: 720 with repower getting hot
Posted By: 7060
Subject: 720 with repower getting hot
Date Posted: 13 Aug 2016 at 8:33pm
My 720 has been repowered with a Honda 24hp. The thing gets so hot under the hood that it melted my battery handle off. It never has ran as good as I thought it should even after I put a new carburetor on it. I decided to mow my whole yard at once today without taking a break and letting it cool, and the think started puffing white smoke towards the end so I idled it down and it would surge and puff black smoke. Checked the oil and the thing burned the oil below the dipstick in the time it took me to mow. Does anyone else have a problem with these conversions heating? Wondering if it's not getting enough air flow. Maybe time for another engine as it sounds like a knock when I shut it off.



Replies:
Posted By: Tracy Martin TN
Date Posted: 13 Aug 2016 at 8:59pm
If you don't push the handle on battery down it will melt them, Onan or Honda. I put a new battery in mine , Onan engine and it softened the top of battery. They might of had a heat shield, but mine is long gone if it did. HTH Tracy

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No greater gift than healthy grandkids!


Posted By: macvette
Date Posted: 14 Aug 2016 at 3:10pm
Yes, there is a factory heat shield that was held down  - at least on my tractor - by a spring on each side.


Posted By: 7060
Date Posted: 14 Aug 2016 at 3:27pm
Does anyone have a picture of the heat shield? I actually thought about making one. I'm also thinking I'm going to put a 10" electric radiator fan on the inside of the grill to help cool things off. The knock isn't there today, I think it might have been pre-igniting the fuel from being so hot. It seems to run fine now.


Posted By: Dan73
Date Posted: 14 Aug 2016 at 3:28pm
Sounds like time to remove the hood.


Posted By: 7060
Date Posted: 14 Aug 2016 at 3:50pm
I would like it to run as good as it looks, it has fresh paint.


Posted By: Tracy Martin TN
Date Posted: 14 Aug 2016 at 9:32pm
Originally posted by macvette macvette wrote:

Yes, there is a factory heat shield that was held down  - at least on my tractor - by a spring on each side.

Can you post pics of it? Thanks Tracy

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No greater gift than healthy grandkids!


Posted By: Steve in NJ
Date Posted: 15 Aug 2016 at 6:38am
Usually, one of the most popular problems with an air cooled engine running hot is its to lean I've found in my experience with workin' on em'. You mentioned you installed a new Carburetor. Did you ever adjust it to the engine. You might need to fatten up the air/fuel mix a tick to get it to run cooler. With a little bit more mix, it may run a lot better for ya to. Doesn't take much...
Steve@B&B

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39'RC, 43'WC, 48'B, 49'G, 50'WF, 65 Big 10, 67'B-110, 75'716H, 2-620's, & a Motorhead wife


Posted By: 7060
Date Posted: 15 Aug 2016 at 9:27am
I tried adjusting the old carb and couldn't get it to run any better, so I thought I would just buy another carb and try that. I've had trouble with the vacuum fuel pump before so maybe it's not feeding it enough fuel. Yesterday I ran it again and it ran great for 30 minutes and then I started noticing white smoke and it started getting low on power and then just died. It started right back up choking it and I drove it over to the garage and shut it off. I can't imagine what would be going on, but I'm leaning towards a $700 preditor version of that engine and the cooling fan in the grill. I love the mower when it runs good, but I'm getting tired of working on it everytime I mow the yard.


Posted By: Tracy Martin TN
Date Posted: 15 Aug 2016 at 9:58am
Put an electric fuel pump on it. Allow the bypass fuel line to work properly. There is no comparision to the vacumn pump. HTH Tracy


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No greater gift than healthy grandkids!


Posted By: ac720nut
Date Posted: 15 Aug 2016 at 2:15pm
Do you have all the shielding in place as with the Onan? if not it's going to run hot


Posted By: macvette
Date Posted: 15 Aug 2016 at 2:43pm
Have never had good success with trying to post pix on the site, but could email a couple if I had your email address.

Under the shield, there is a piece of asbestos.


Posted By: TREVMAN
Date Posted: 15 Aug 2016 at 7:57pm
Do you have the bottom sheet metal on? If not it will over heat. Electric cooling fan not a bad idea though...Trev.


Posted By: 7060
Date Posted: 16 Aug 2016 at 7:52am
Yeah it's got the sheet metal on it the engine. And I wrapped the exhaust in foil to try and direct more heat out the pipe. I bought an electric fuel pump and 10" cooling fan I'm going to try that.



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