IH CUB LoBoy Series - 154, 184, 185 Forum -- Questions and answers to all of your LoBoy related issues.
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Last summer the 1977 cub 184 lowboy just didn't seem to have the power it should have. I was thinking the rings might need replaced but it has 100 pounds of compression in all 4 cylinders. Supposed to have 130 pound. is this a case where it is time to replace the rings or not? Spark plugs look a bit carboned-up on the outside of the curved Grounded part but not anywhere near the spark gap area. Could it be running too rich? Timing?
Starts pretty easy and runs good just not the power I think it should have. Bogs down and will even stall sometimes while mowing where it used to just trudge right through. Old style ignition and not electronic. If I can provide any other info to help those of you with the expertise that know these machines to make an educated guess or things to check, please let me know. Thanks.
Sounds to me like it needs a good old valve adjustment. When it comes to power, they may run well, but if it has not had it's valves adjusted in a few years, it just will not power through.
Give it a try, it is not hard to do.
thanks Dale, I will pull the cover and check their clearance tonight.
Also pull the distributor cap and look at the points and check timing. 110# compression is still a good engine.
I think the valves were okay. I adjusted a couple that were less then the recommended .015" but, not by more then a thousandth or two. Didn't get the exhaust off so I can't see the valve tops to see what they are like. That manifold is really on there. Thanks. I'll look at the timing. I'll need to dredge up a timing light somewhere.
Pulling the manifold will only allow you to see the valve stems. Only puling the head will allow inspection of the tops of the valves and their seats. I wouldn't pull either of them though. Just stick with the simple stuff for now. Let us know how the ignition systems looks and the timing.
Pull the points out and re-file them nice and flat and then re-install and reset the gap. Also make sure that you are getting a nice strong 1/4" to 3/8" blue spark at the end of each spark plug wire.
I will try to get in there today and check this out. What does it mean if the spark isn't blue? A bad coil? Thanks.
Okay, I reset the spark plug gap to the .023" recommended in the manual, cleaned and reset the point gap to the recommended .020" and checked the spark. A nice blue spark about 3/8 to 1/2 inch. I'll check the timing and rpms once I round up a tach and timing light. Anything else I should be checking? Thanks.
Once your sure the ignition is working properly and the timing is ok i would ckeck out the air cleaner and make sure the fuel delivery is spot on too. Then i would change the crankcase oil and oil filter and add seafoam with a tank of fresh gasoline with some seafoam added to the gas too and run it. Run it till the idle speed picks up on its own and do a compression check again. The seafoam will free, reseat and lube the piston rings plus lube the valve guides and free sticky valves. The performance of the engine will change just by adding seafoam. With most engines they just need an additive as a wake up call. Trust me this stuff works when these machines just sit all winter. I add seafoam in the gas and crankcase every fall.
I'm technically misunderstood at times i guess its been this way my whole life so why should it change now.
I ordered a timing light and a tachometer to see just where this is firing and how many rpms it is running at. I want to determine if I am over revving or under revving at full throttle. That could be an issue too I would think. I know I used to have one of each laying around the shop but, the friend I had borrowed them from probably reclaimed them.
What is the proper way to adjust rpms? Adjusting the carb, engine timing or the settings for the governor? I'll do some reading this week in the manual if I can. Thanks.
Do check the air filter and fuel flow first. After that, check timing first then RPM's.
Start by making sure timing is near 0 degrees at an idle with timing light.
Move throttle to wide open (no load). Verify that timing moves to near 16 degrees mark. If it doesn't move, then there is a problem with the timing advance mechanism in the distributor.
Set timing (at wide open throttle) to 16 degrees mark.
Don't worry if it isn't at 0 degrees at idle.
Set RPM's of the engine to the manual specified 2400 RPM by adjusting the governor.
If measuring the RPM's of the PTO then the PTO will be turning at 1970 RPM at wide open throttle no load.
Note: if your machine has been rebuilt with flat top steel pistons, I wouldn't push it to the 2400 RPM's. 2400 is only for the aluminum dome topped pistons. Older Farmall Cubs use the flat top steel pistons which are rated at 1800 RPM's. (don't ask how I learned this, it was an expensive learning opportunity)
Your 184 may be running a bit rich, but I wouln't touch the carb until the other items have been looked at. May not need any adjustment if the timing was off.
184 w/ Creeper & 3-Point
IH Model 15 Tiller
Based on what? In other words, seems to mow harder, less RPMs, etc???
If it seems to mow with less power you may also want to consider the pto drive train, mower bearings, sharpness of the blades.
If you feel it is the engine, I typically like to do only one thing to try to isolate the problem but in reality it may be easier to do what Eugene typically recommends: a full tune up.
Ok, I got a timing light and digital tach a couple days ago and finally had time today to check things out (it's raining so other stuff can finally wait). I wish I had seen this post sooner. The air cleaner looks good and the breather tube is clear. What else do I need to check with the air and fuel?
Anyway, I put the timing light on, warmed it up and it was way fast even on idle (which is way high but we'll get to that in a minute). I set it for 16 degrees BTDC (that was before I read this post). I reved it up and it does not advance when in full throttle. Stays right at 16 degree BTDC. I will readjust to zero at idle and see if that makes a difference in the advance.
Now, RPMs: Using a digital tach where you put a piece of tape on the pulley and the reflection from a laser gives you how many times the piece of tape passes the light. According to it, I am running about 1350 rpms at low idle (I know it is way too fast.) I had suspected it was fast but, I had no idea it was that fast. At full throttle I get a reading of 2086. So, does this tell you anything as to what to adjust? I will head back to the shop and see if adjusting the timing top zero at idle helps with anything. Thanks.
Okay, I lied. I rechecked the air cleaner and it looks much more like it needs changed then I remembered it. So, another i on order. Will be in tomorrow. That is one pricey air cleaner at $35.00. Will wait for that to do any more adjusting. Did set the timing at low idle to zero and it stayed there on high idle as well. So I set it to 16 degrees BTDC at high rpm and it stays right there when I bring it back down to low throttle.
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