Title. Struggling with hot starts.

-Starts cold just fine
-Hot will have 1-2 slow cranks, then fire up. Or it will not fire at all. I then leave the hood open to cool the engine bay and it does 1-2 slow cranks then starts.

Where should I start looking?

-new battery
-battery connections good
-alternator new
-new ignition control module

What else could I look into?

I use it for lawn care, so I kinda need it to start when it's hot out 😅

 

Whenever starter trouble strikes, look to the sky! Is it a bird? Is it a plane? No, it's everybody's favorite superhero to the rescue! Voltage Drop Man!:

https://www.ford-trucks.com/forums/1...w-starter.html

 

Thanks!!

 

That is the first place to start because of the slow crank (timing as a guess?) but I will guess once you have that under control then you will have a long cranking till it fires off.
This is a problem we all have the have carburetors on our motors.
Dave ----

 

Timing was my first thought too.
Do your battery cables look like this ? Or do you have some clamp on terminals ? That's the chassis ground in the 2nd pic.

How old is your battery ? Most auto parts stores will test the battery for free.

 

Forgot to add something. Before testing, duplicate the fault conditions as much as possible. In other words, make sure the engine is good and warm.

You mentioned everything is fine with the engine cold. This is because compression is lower and the starter has an easier job to do. With the engine warm, compression increases and the starter has to work harder to get the crankshaft spinning. Most likely something in the starter system is marginal, but supply still exceeds demand when the task is easy. But when you increase the demand, the same supply is now insufficient. The result is slow cranking speed when warm.

Please be sure to report back what you find. To save time, here's a reply you can copy and paste:

"Karl, you are amazing. Your test procedure led me directly to the fault and all is good now. As wonderful as you are, how do you stay so modest? That must be really difficult. I bet you smell nice, too."

 

When I saw the users name I thought of you Karl and wondered if he smelled nice too as he is well dressed
Dave ----

 

My timing was perfect probably 8-10 months ago. Could it have gone out of time already?

 

Battery is brand new. I will send some photos when I get home. My battery cables on the terminals positive and negative are replaced within the last year

 

I have not had to touch my timing in over 45,000 miles or nearly 35 years. If the timing is correct, then I would look at something in the starter system getting hot.

Edit, correct that, the mechanic replaced the dizzy some 11 or 12 years ago.


How close is the exhaust to the starter ?

Next it cranks slow, stop, take a hammer and tap the solenoid and or starter. See if it cranks faster afterward

Maybe have a meter and check battery voltage at that time too.

 

Unplug the coil when you have the problem, and see how fast it cranks.

Right now I am trying to figure out how a engine has more compression when it's hot. I will have to think on that for awhile. Hot air is less dense isn't it?

 

I may have oversimplified my theory on warm engine = higher compression = increased load on the starter. The piston rings do seal better when warm and fully expanded, for example. Oil has a had a chance to splash around and improve sealing, too. But that same heat can also affect the starter motor and reduce its power output. Same thing with any marginal cable connections. But for the most part, the starter system has a higher power output (supply) and less demand when cold. When warmed up, starter power output (supply) can decrease while the demand increases. The only time anybody will notice a problem is when demand exceeds supply, which causes slow cranking.

 

Karl, you got me thinking, Does the CCA on the battery make a difference. My truck came with a 560CCA, I put a 700CCA battery in


I played the other day, a 230CCA out of my John Deere, would not crank my Husqvarna which came with a 260CCA battery. Both batteries are good.

 

I would check your choke. I noticed after adjusting mine i started having hot start problems. When i adjusted it back the problem went away.

 

It's okay, don't be afraid of this new sensation. There's a first time for everything.


I'm not well versed on the subject of CCA. Don't quote me on this, but I think it's one of those old rating systems that are somewhat arbitrary today. For example, a "10-ply" tire doesn't necessarily have 10 plies anymore. That's an old system where the number of plies corresponded to the weight capacity of the tire. With modern materials, the actual capacity is the defining aspect, not the number of physical plies, yet the old nomenclature is still used.

With that said, there's no harm in going with a little higher CCA rating on your battery, within reason. Maybe 20% or so, just a guess. If you go much higher than that, physical size may be an issue. With the increased electrical capacity, the original charging system may have trouble keeping it topped off, too. Think of a battery as a pressurized water tank being filled with a pump, or a big thick-walled balloon being inflated with an air pump. Increase the size of the tank or balloon too much, and the stock pump will have trouble keeping up.

What size battery to select? I've always just gone with whatever option the parts guy found in his books. If presented with more than one option, I'll usually go with the higher capacity.


Hmm, that's odd. The difference is only about 13%. I'd think the lower capacity battery could still get the engine started, although with less reserve. I'm thinking there must be something else going on.