Just upgraded my stock GTR35 with 100hrs on it. Put a carb kit on it and had the heads worked. Got it back and took it out the next day, ran 31mph in open water with 3 batteries, loaded ice chest, 2 people, and trolling motor. Went to turn the motor off to fish and it started "dieseling", when started back up to head home I could only get 2700rpm out of it. Brought it to GT and they told me I "rolled the cam". I had him put a high performance cam on it to prevent breaking the cam again. I've heard a lot of people say that putting a cam in will mess up the engine...I'm wondering how true this is. With a 42mm carb kit, head work, and high performance cam, how long does the engine normally last?

It should be ok for a while if Hoyt did it. They don't get too crazy when building an engine. They give you a good mixture of performance and reliability. They know what works and what doesn't.

But also keep in mind that it's a Briggs so it can happen at any time. Make sure to keep your CC bolts tight.

Sorry to say, sometimes shit just happens.

But could you imagine the replays if this was a bps cam

In my opinion a stage 2 isn't detrimental to the longevity of a motor at all. I don't think you will get any less hours out of a stage 2 than a stocker, especially if you keep the valve train timed (aka keep your lash in check).

Quack, it may not have had anything to do with it but u HAVE to run a high zinc oil in these flat tappet engines. Most oils nowadays don't meet these specs even when they claim to have "high wear additives". This is very important. Oil just ain't oil anymore. It ain't rocket science either it's just that the recipe sorta left an ingredient out that these kind of engines need, but ya probably knew this already

X2 ^^ very important, and most often overlooked

Zinc and other non-friction additives (slippery stuff) have been removed from most engine oils because they were linked to plugging catalytic converters and sensors on automotive engines - not much help but a little FYI.

!?!?!?!!!!???!!?!!!!!

A stage 2 built well will last, and how long is really up to you. I.e. blasting the motor everywhere for long periods of time and not changing the oil frequently are two tickets to a new block. I change the oil and filter in mine alot now. Keeping the motor lubricated and relatively cool are very important. Typically my running rpms are 4100-4300 It can hit the limiter at 4750 but IMO gaining a couple mph by running 4700 rpms isnt worth the stress thats being put on the motor. Also IMO its good to let the engine idle for a couple minutes before shutting it down after running it for a while. Circulating the oil and letting some air flow across the block at low load will help it cool down and definetly prevent it from dieseling.

It doesnt circulate at all if its off.

just saying if you want to cover your ass

That's because it's a fucking Diesel engine!!! Gasoline engines aren't supposed to "diesel" and if they do, you've got a fucking problem. Period. It's lean on top for some reason or something is causing a hotspot in the combustion chamber that makes the motor keep igniting the fuel on it's own after you quit giving it ignition. Neither one of those conditions are good. If you run your shit like that, don't be surprised when one day it detonates and knocks the rods out the bottom of the fucking block. I'm not saying it's a bad idea to let a motor cool down. I'm saying that kind of problem needs to be addressed as soon as possible. I'm the asshole and all I was trying to do was help.

Some people can't be taught they were born with to much ignorance


Sent from my iPhone using

I never said dieseling was a good thing either all i said was if your worried about it doing that theres a way to ensure it doesnt do it. I learned that from a few airboat owners the cost to get the problem fixed $$$ the cost to just let the motor idle a couple minutes before shutting down to prevent the dieseling... $0

The cost to get the motor right is probably less than $10 worth of carb jets

It could be something else, but it isn't likely to be anything other than a carb issue. Matt says lean, but i'm pretty sure a rich condition can cause it as well. Rich would leave carbon deposits and unburned fuel. Lean would create excess heat and/or hotspots. Either way, neither are good. I'd get it figured out.

My airboat diesels with cheap fuel. It does help to let it idle down to cool it somewhat. Although idleling at a low rpm is not the answer. The fly wheel is not spinning fast enough to pass enough air across the block and not enough oil is pumping. I notice this in my airboat when idleing at 800-1000 rpms the temp climbs and about 1500-1800 it starts to go down.

Two different beast but the same principle.

Detonation is different than what I call dieseling. If we're talking about detonation, then I agree with you.

What does rolled cam lobe mean

Flattened so you loose your lift

Gear head slang for one of the lobes of a cam that becomes worn down beyond specs usually a premature condition due to adjustment, oil or over revving.

Roger that