Jump to content

Unofficial Home of Old Simplicity & Allis-Chalmers Garden Tractors

RedRock

7790 diesel after sitting with water in fuel

Recommended Posts

RedRock

My 7790 sat for some months with water in the fuel; I attempted to start it. Big oops. A friend/small engine guy is working on it. Currently it will run well at full throttle but will not run at lesser rpm. Tank and lines were cleaned and obviously fuel is now being burned.

Any suggestions as what to do next? Thanks, RedRock

Share this post


Link to post
Share on other sites
fishnwiz

Welcome to the site.

We have several 7790 owners in the membership along with a few diesel experts who will be along shortly to help you with your issues.

Best of luck.

Share this post


Link to post
Share on other sites
farmtoybuilder

If you haven't cracked ( barley lossen ) the injection lines at the nozzles, Do them one at a time with it running or both by just cranking engine over. Water won't go through nozzle! You could still have water and air in them still. Put battery charger on it while cracking also! as you'll need it. Don't get your starter to hot! Also bled injection pump again and make sure you have fresh fuel at bleeder. If it had a bunch of water in the pump and you didn't remove injection lines at nozzles. I would remove lines from nozzles and blow out the nozzles and crank engine over and allow fuel to pump through lines. Then reinstall, tighten both and try. You may have to crack them again to get air out. I would also get some fuel conitioner and put in it also! Let us know what it does.

Share this post


Link to post
Share on other sites
RedRock

Taking suggestion to my friend/mechanic today. I appreciate the input. Additional info would be that the fuel filter separated from its base when I attempted to start the Lombardini. By the way my friend, a Cub specialist, has become intrigued and has a line on one to buy for himself.

Thanks, RedRock

Share this post


Link to post
Share on other sites
RedRock

Yes, BLT. It does start and go to WOT immediately. Does not smoke. Next step to be taken is to ultra clean injector assemblies. Low speed cable was disconnected, but connected does not fix problem. Unexplained crud inside engine, and the repair man wonders about malicious damage. Tractor was running correctly at all speeds when parked. I have to evaluate whether I can afford to go forward at the current rate with no guarantees. Thanks for help so far. RedRock

Share this post


Link to post
Share on other sites
BLT

Injectors don't appear to be the problem, controlling the speed sounds more like it, and comes from the injector pump. You can stop the engine with the pull to stop cable, correct?

Share this post


Link to post
Share on other sites
farmtoybuilder

If that's the case the control rack in pump is stuck_ gummed up. And will have to be removed and taken to injection pump shop to fix! And you'll need a mechanic thats worked on diesels to remove, or get a service manual to see how it comes off. Most of these small diesels have govner springs that need removed before you remove pump. Maybe another member that has this egine can help you.

Share this post


Link to post
Share on other sites
RedRock

Thanks a ton,farmtoybuilder. That sounds consistent with what has already been treated in that many other possibilities have already been answered. The shop guy has a place and/or an experienced friend for that kind of work. I appreciate the input. I had gotten a little confused about what to do since costs are piling up. I'll go as far as your suggestion. If worse comes to worst, I could use the hydrostatic transmission/rear end on a chassis with a gas engine since the only Lombardini I know has been spoken for. RedRock

Share this post


Link to post
Share on other sites
RedRock

Brought the tractor home yesterday. Injector pump gum removed, injectors cleaned in a sonic machine and much crud removed. New fuel hoses and filter. Tank cleaned. Stopped and gave a quick car wash treatment. Went out in the yard to check on it last night as if it were a new puppy. Thanks for the helpful comments, all who responded.

Share this post


Link to post
Share on other sites
farmtoybuilder

Thanks for update. Glade you got it going again! :D

Dang shame our gas & diesel fuel is Crap today and causes all these problems. We have quite a few old tractors that only get started a couple times a year and I cringe every time we go to start them! We didput some seafoam in most them last fall. So we'll see how they fair soon!

Share this post


Link to post
Share on other sites
RedRock

I now have Seafoam in current fuel. I also got lucky when a Shell station close by started carrying non ethanol. I will use it for all my small engines. I know my Pontiac Vibe got 38 mpg as opposed to 32 on a trip to Norfolk and back using non ethanol. Snowing here in Virginia, but there are trips in the future for attachments. 4i4i

Share this post


Link to post
Share on other sites
acfarmer

I run quite a few diesels and I treat the fuel in them with Seafoam on a regular basis it'll keep the water out of the fuel and from collecting at the low places in the lines and filters.What attachments are you looking for I have quite a few.Live near Charlottesville.

Share this post


Link to post
Share on other sites
RedRock

acfarmer, i have a deck. i also have a brinley plow, disk and cultivator that came with a walk behind tractor...My 7790 has the rear lift mechanism but no round tube to which to attach a sleeve hitch..

sleeve hitch attachment point

sleeve hitch...snow/plow blade...tiller...

possibly road grader belly mount blade...

Share this post


Link to post
Share on other sites
SKIFOOF

that's how I destroyed my 920,sat several years went to wot,engine shot,found rack in pump very stuck,i tapped on it pretty hatd ,never got it to move,did find another pump though,never start a diesel that's sat without being ready to cover air intake in case it runs away!

Share this post


Link to post
Share on other sites
mtoney

Rule number 1 when starting a long dormant or freshly rebuilt diesel is to have a good clipboard or piece of wood handy to place over the intake incase of a run away. With no throttle plate like in a gasser, given a supply of fuel, or even crankcase oil, they can and will go crazy if given the chance. Mikie

Share this post


Link to post
Share on other sites
RedRock

The throttle cable for the 7790 has pulled free or broken at the control lever. When removing the cover to access this area, what precautions must I take to avoid compromising the mechanism that activates the pre-heater? I don't want my too often rip and snort to become an "Oh, oops" situation.

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now


×