Starter turns engine very slowly when hot.

[dank]

Hello,
This is my first post. I've gone through all previous threads but couldn't find anything on this topic. The starter works fine when the engine is cold, but it can hardly turn the engine when it's hot (or not at all). I had a similar problem on my 72 Econoline many moons ago, but can't remember if the problem was the starter or something else... can anyone help?
Thanks in advance,
Dank

[myplace 46]

Hello,
This is my first post. I've gone through all previous threads but couldn't find anything on this topic. The starter works fine when the engine is cold, but it can hardly turn the engine when it's hot (or not at all). I had a similar problem on my 72 Econoline many moons ago, but can't remember if the problem was the starter or something else... can anyone help?
Thanks in advance,
Dank

welcome Dank.
sounds like what my starter is beginning to do also.
assuming your battery is in top shape (it can start fine when cool and give out when motor is hot) then it is most likely the starter is just showing it's age. you can get rebuild kits for them if it is still in good enough condition to rebuild, otherwise you;ll have to buy a new or rebuilt starter. you might try eBay. also when Vic (admin) sees your post I'm sure he'll kick in some additional info, he's full of it... I mean info
good luck
John
:wink:

[Guest]

Welocme aboard, dank. I can't add more than what myplace stated but I'm sure there will be more answers before long.

[Fatwing Chris]

Welcome to the best 1200 forum going.I would also agree that it sounds like the starter is on it's way out,but you should verify your connections first.All of your Bat.+ and ground cables.

[Tropicalsuns]

Mine does this as well...more if I do not start in neutral.

[Fatwing Chris]

Sounds like your clutch could be dragging Marty as well as a starter going south.

[dank]

An update: I requested help from a member of my vintage group, (Rod Sheridan) and here's his response. I haven't had time to check connections, etc, but I'm planning on taking all necessary steps before pulling the starter! Thanks to all who responded for their feedback, I'll post my findings as soon as possible:

"Hi Dan, a hard starting problem with a hot engine is common, although counter intuitive.

A hot engine is normally easier to crank than a cold engine, so a starter motor should be able to crank a hot engine faster than a cold engine.

The starter motor however is a different story. Copper wire has a normalized positive coefficient of resistance of approximately 0.004 ohms per degree Celsius.

A starter motor at 0 C, with a normalized resistance of 1, would have a resistance at 80 C of approximately 1.32. This substantial increase in resistance reduces the maximum starter motor current, resulting in less output torque.

If the engine manufacturer has not taken adequate precautions to control radiated and conducted heat into the starter motor, and hasn't adequately rated the starter and battery to accommodate this rise in resistance, the system won't work well at elevated temperatures.

So if your battery is new, connections are tight, starter is in specification, engine has no mechanical problems and it won't crank when hot, someone at Honda shaved too many pennies from the copper and battery budget. Obviously if your battery, starter motor or engine aren't in specification, you need to fix those items.

If it's any consolation, I had an 83 CX650E, high compression, short stroke twin cylinder engine. When hot, if the battery was more than 2 years old it wouldn't start.
I would give the old battery to a friend who had a 4 cylinder 750CC Suzuki, and he would use it for 2 more years, no problems.

Regards, Rod.

[admin]

I had the same problem with my starter and it drove me nuts. Starter worked great when cold but barely turned over when hot. Had to take the starter out and disassemble it, clean it and inspect and test it for shorts and opens electrically and it proved good so I greased it all up, put new brushes in it and reassembled it and put it back in and be darned if it still did the same thing when hot, even had to push the bike a few times because it would not start hot. Finally I tracked my problem down to a dirty start button switch. This switch is in series with the headlight and when it gets hot it resists and won't conduct electricity to the starter, hence the slow starting when hot problem. I took the switch apart and cleaned it and it's worked fine ever since.

You may or may not have the same problem, your problem could be in the starter relay, starter brushes or springs, could be a loose brush ground plate or even just some loose wires. I suggest that you order a starter rebuild kit from Ebay and start by rebuilding you starter because that's a good start. It's not hard to do and we are here to help if you need us.

[dank]

Thanks for all the replies, folks. So far I've cleaned and put dielectric grease on all contacts and connectors, re-wired the alternator yellow wires directly to the rectifier bypassing the connectors, added the 12V red wire directly from the rectifier to the battery, and installed a new gel battery, although the old one load tested good, the same reading as the new one. The problem is the same at this time. I haven't cleaned the start button, I'll do that next, just in case, although I don't understand how it can cause the symptoms.
I've purchased a starter rebuild kit, and I'm wondering if you have to drop the exhaust headers to remove the starter?.
Thanks in advance,
Dank

[admin]

You do have to drop the header to get the starter out, basically just remove all the nuts and loosen the joint at the muffler connection and lower the header then rotate it out of the way. You must also double nut the stud closest to the starter to gain clearance to remove the starter.

The reason the start button can cause resistance is that it doubles as a shut off/on switch for the headlight and heat can build up and cause resistance if dirt builds up on the contacts. It doesn't happen in every case but it did happen in my case. Small parts and springs inside so be careful. I stretched the spring ever so slightly in mine to increase tension. Don't forget to grease the moving parts when reassembling.

Good luck on the rebuild.

[dank]

Many thanks for the advice; I'm waiting for the rebuild kit to arrive, meantime I'll clean up the start switch and try it out again.
Dan

[dank]

Hello again,
Well, I have done the start button cleanup, and it made no difference. Boy, you were not kidding when you said to be careful with all the small parts in there! It was a good exercise in patience and dexterity!
My starter rebuild kit just got here yesterday, I'll tackle the rebuild next.
Thanks again,
Dank

[admin]

Too bad you didn't get lucky. At least you know the start switch is clean.

Good luck on the rebuild.

[dp]

I just went through this on my 84 I, had the exact same symptoms, good cold start, slow or no hot start. Using a rebuild kit from Stocker's Starters on the web, I replaced all the ball bearings, the single bushing, brushes, brush plate, lip seal, O-rings, and fresh grease in the planetary gear set. After that experience, I would not change the small ball bearing on the commutator end unless it was bad. Mine was tough to get off without damaging the end of the commutator. Also undercut the commutator insulation between each bar with a hacksaw blade to clear out carbon. One other tricky point was getting the planetary gear set meshed properly on reassembly. The old brushes looked good, but that end of the starter had a pile of carbon dust, so I changed them out anyway. Also, the planetary gear set grease was hard and practically gone. It seems to spin over faster now and as of yet no more hot start problems. I would be interested in knowing how your job turns out & good luck!!

[bluewing]

I had a similar problem, my bike would start cold no problem but would turnover slower when warmed up. One day I went to start the bike and it would not turn over at all, it turned out to be a bad battery. I replaced it and it now starts good hot or cold.