Husqvarna 450 Rancher Overheating?

[MikeS]

Been having some issues with my 450 Rancher. Have had it for a couple years. Fair amount of use as wood is my heat source during winter. It conks out after about 15 minutes use and is difficult to restart. New filter, plug and fuel filter. Cleaned carb. Same issue. Seems much hotter than normal. Took it apart and blew everything off with compressed air. Would improper fuel/oil mix cause this?

Mike

 

[Bob Hedgecutter]

Lots of things can cause excessive heat retention and build up- from dull chains pushed hard, to oil and sawdust puree packed throughout the saws externals- so air cooling is not cooling.
Sounds like you coil is cooked or in the process of being cooked. Starts and runs until heat builds up in the coil and it stops- wont start until it has cooled down again. Can also cause altering timing as the coil heats and out of time spark can increase heat levels.

That taking apart and blowing off with compressed air thing- has to happen fairly regular. A bit of preventative maintenance going a long way towards tail chasing throw parts at it repairs.

 

[MikeS]

Is there a way to pin down whether it's the coil or not? Other than replacing the coil, that is.

 

[Bob Hedgecutter]

Is there a way to pin down whether it's the coil or not? Other than replacing the coil, that is.

Not fairly and squarely- as the internals of the coil heat up, some of the messages needed fail to get to where they are needed within the saws ignition system- kind of like saw dementia. Think of the coil being your saws brain.
Was there a lot of oily grime packed around the coil before you blew it out with compressed air?

 

[Bob Hedgecutter]

You could try running it with the top cover off until it quits and immediately do a spark test with either an inline tester or grounded plug- but the plug will be hot to handle.
If you have no spark, odds are the coil is damaged- or some part of the ignition system is causing a short to ground. If when the saw cools down you have good spark again- go back to thinking coil.

 

[MikeS]

A lot of crap came out, yes.

 

[Bob Hedgecutter]

A lot of crap came out, yes.

Another reason to suspect the coil, it is cooled by air circulation from the flywheel, if its air gaps from the case are packed full of insulating debris- heat cannot get out and cool air cannot get in. Cooks the internals of the coil.

 

[MikeS]

In checking online for parts, I noticed lots of brands of coils for Husqvarna. Any you would recommend?

 

[Bob Hedgecutter]

In checking online for parts, I noticed lots of brands of coils for Husqvarna. Any you would recommend?

As a elimination test bed- the cheapest that fits from Amazon or somewhere?
Will allow you to test for continual running and easy restarting once saw is warm. But may not last well in the long run. But doesnt cost much if it is not your coil giving problems?

I am fairly convinced it is a coil issue- but I am also typing this from a hospital bed- so who knows.

If you have a buddy or neighbour with a similar sized 4## saw, the coils should swap over and allow you to test- or if a repair shop has a wrecked saw- run over or straight gassed- they can be had fairly cheaply and will have all the parts you need, plus a whole lot of other handy parts.

 

[MikeS]

Thanks for your help and I hope you have a speedy recovery.

I guess I will base my part choice on the number of positive reviews

 

[Bob Hedgecutter]

I seem to remember there were some issues surrounding limited coils or coils that gave an easier starting mode and then transitioned to normal running after initial start- I do not think this is what is happening with yours.
Google search Husqvarna 450 Rancher coil problems- might give you some interesting reading?

 

[MikeS]

 

[MikeS]

Trying to find the proper coil/flywheel gap for the new coil and am surprised that the info isn't readily out there. Going to feel dumb if it's in the manual but I haven't found it so far. Does .009 to .011 sound right?

 

[Bob Hedgecutter]

Loose coil, business card for an air gap feeler gauge, hand rotate flywheel till magnets grab coil- tighten mounting bolts to coil, rotate flywheel to remove business card- done.

 

[MikeS]

 

[huskihl]

As a elimination test bed- the cheapest that fits from Amazon or somewhere?
Will allow you to test for continual running and easy restarting once saw is warm. But may not last well in the long run. But doesnt cost much if it is not your coil giving problems?

I am fairly convinced it is a coil issue- but I am also typing this from a hospital bed- so who knows.

If you have a buddy or neighbour with a similar sized 4## saw, the coils should swap over and allow you to test- or if a repair shop has a wrecked saw- run over or straight gassed- they can be had fairly cheaply and will have all the parts you need, plus a whole lot of other handy parts.

You need to quit stepping on that banana peel. Every time you do it you end up in the same spot.

 

[MikeS]

Coil I ordered didnt work, sending it back.

 

[Bob Hedgecutter]

You need to quit stepping on that banana peel. Every time you do it you end up in the same spot.

Which peel is that?