While speaking to the guy he said that Briggs is recommending that any motor that comes in, that they should replace the stock aluminum push rods with the same steel push rods used in the exhaust. Apparently the heat from the Ethanol gas combustion is causing the stock push rods to deform. We began talking about higer RPM's, and he said the stock arms begin to stretch at sustained RPM's above 4100. Just FYI-- Not sure if anybody else has heard this. It definately makes me want to swap out at least the push rods, to Stainless steel...

I thought I would pass the information along

y'all be sure to send all those "bad" aluminum push rods my way

Coondik- I this BS? I trust your opinion more than I trust some guy in the store, but if it had any validity to it, I thought I should pass it on!

Craig- Exactly--they are cheap and easy to install. That is why it would be a no brainer. if there is any validity to it, might as well spend a few dollars to save problems down the line!

The again, like I asked Coondik, it may just be BS or a misinformed opinion, in which case you are exactly right! Thx.

It is a heat related issue. Apparently the ethanol burns hotter than the standard fuel the aluminum was designed for, and it is causing the rods to deform under this heat. I am just learning about the internals of these engines, so I am just repeating what I was told! Keep in mind he doesn't work on mud motors, but he is an authorized dealer and repair center for Briggs, and this is what Briggs is telling him to do. This about all I know!

Good to know about Craig-- didn't mean any disrespect there Craig. LOL

If these motors were not designed to burn that hot then the cast aluminum blocks will become a weakness also... I would worry about that more than an aluminum push rod.

the block is a lot thicker and heavier than the flimsy stock push rods. apples and oranges.

SP, push rods are normally bent due to rocker arm assembly failures (bent or broken rockers or rocker arm studs coming loose) are excessive carbon build up on the valves. If a rocker arm cracks, bends, or breaks or if a rocker arm stud backs out or comes loose there will be an increase in clearance between the push rod and rocker arm which will sometimes allow the push rod to fall out of the rocker arm. If the push rod DOESN'T fall out of the rocker arm, push rod type and strength will determine the life of your engine at this point. If you have the stock or aluminum push rods they will be bent when the cam opens the valve because the valve will most likely travel to far and will then be struck by the piston. Normally, 20 bucks and 20 minutes can fix this problem. This is what you want to happen. If you install big beefy heavy stainless push rods and the above happens, well, good luck. If the push rod doesn't bend, this can cause valve restraint which will cause the valve to be broken when the piston hits it. Any number of things can and will happen including catastrophic engine failure such as major cylinder and/or block damage once this takes place. I know people who carry spare push rods with them just in case something like this happens while on the water. I personally would prefer 20 bucks and 20 minutes over a new block! Hope this helps you understand this a little better.

Oh, no offense taken.

I forgot to add, carbon buildup on the valves will also result in bent push rods since the valves cannot fully seat. I just went thru this on my dad's lawnmower engine.

Would any of you knowledgable guys venture to say that the increased mass of a stainless pushrod would have an effect on the valve train in the upper RPM range?

Craig- Yes this is very helpful...and your explanation even it makes sense to me! When you think about it that way, the stock rods will remain in my engine! Thx again.

Just asking?

So do these engines need to be tuned accordingly to run ethanol? Im sure stoichiometric for ethanol is considerably different if problems are being had with heat on the outside of the cylinders?

No. They just need to be ran with some sort of fuel stabilizer. (Stabil) Outboard engines are catching hell right now because of the added ethanol.

i think de only solutions are water jackets & a metric turbo. what do y'all think de increase one DSL will be?

Ethanol is nothing new, it's been pretty much blended in up here for the last ten years at a 10% ratio. As far as running hotter this is the first I've ever heard of it and I believe it actually burns cooler due to increasing the octane rating.