Anyone want to take a stab ad diagnosing this engine? Video inside.

[Bosunsmate]

a short in your kill circuit perhaps

 

[RaisedByWolves]

a short in your kill circuit perhaps

Kill circuit is dead as far as I can tell on this motor. I did move the wiring around a lot while replacing the head gasket so maybe Ill take the ground wire off to be sure.

Looking at some videos and the comments given this could be a faulty temp sensor or a bad powerpack.

Heres a vid of very similar symptoms.


https://www.youtube.com/watch?v=go2w3t2Q9Bs

And another with the reply from Kramden leading me to believe it is the temp sensor as it idles fine and only happens when the engine gets warmed up a bit, then runs fine again after shutting down and cooling off.

https://www.youtube.com/watch?v=ZaOq8OtSiK0

 

[Bosunsmate]

Disconnect the temp sensor and try the theory out

 

[oldboat1]

(Remember to re-torque the head bolts and check operating temp.)

Sounds offhand like a motor running out of gas. Maybe the pickup in your tank isn't reaching the bottom -- or maybe you are picking up water down in the bottom. Also wouldn't hurt to loosen the cap to see if that helps (venting issue). If you have access to another tank and hose, might try that with some fresh fuel.

Just guesses, based mostly on the video.

 

[RaisedByWolves]

Yep, it was a bad temp sensor.

I unplugged it before launching and kept the cowl off to check temp by hand and everything is perfect.

I was able to hit 28mph but I think I need to raise the motor an inch or so as its running wet. I put a hydrofoil on it while I was out and while that helped get on plane and made the boat feel like it is on rails, Im still getting a bit of porpoising above 20mph even with the tail and the motor being tucked all the way in.

Oh, did you know the flywheel is exposed just enough to rub your arm when you reach around to feel the head while running? :sad:

Now that it has actually run enough to be considered heat cycled I will torque the head bolts again.

 

[oldboat1]

damned ring gear leaves scars -- need an infrared sensor.

Sounds like progress. Believe the porpoising might be caused by tucking in the engine too far. I would try it in the other direction (wait for additional advice -- can be other causes from hull issues to load distribution, and more.)

 

[Joe Reeves]

]damned ring gear leaves scars[/COLOR]

Yep... damn near lost two fingers back in the late 80's, Hellava scar!

 

[RaisedByWolves]

damned ring gear leaves scars -- need an infrared sensor.

Sounds like progress. Believe the porpoising might be caused by tucking in the engine too far. I would try it in the other direction (wait for additional advice -- can be other causes from hull issues to load distribution, and more.)

There are some dents in the bottom at the transom from the previous owner trailering the boat with a battery sitting between the transom supports which need dealt with. I also need to raise the motor an inch or so to get it set up right.

I would have to say that no, it was not loaded properly with just me in it.:facepalm: Nothing but a deep cycle battery and the trolling motor up front. Without the foil on it the hull was pounding, but afterwards just some slight porpoising.

 

[RaisedByWolves]

Took the boat out Sunday and was pleasantly surprised and somewhat confused.

I got 25mph loaded with me the wife and gear, where as I was previously only getting 22.

Im wondering if on my previous outings after replacing the head gasket if the bad temp sensor was somehow limiting my top speed? I didnt change anything in the interim.

My RPMs were 5750 @ 25mph.

Any thoughts?