r/engines

95 4.3 vortec carb engine, had to swap blocks cause the last boat owners didn’t winterize correctly. Got it all back together with the mercruiser upper half and can’t get it to fire. Thought I got timing correct and distributor pointed at 1 when at tdc but all I’m getting is backfires on crank. It sat for a good bit so do I start with carb rebuild, timing, or did I do something interal wrong. Any advice helps. Thanks

Vertical lines in cylinder wall - 2023 4Runner with 34k miles, normal? It’s under an evaluation period so I can’t tear it apart to feel it with my nail.

Edit: I should have added here that it was a Carvana purchase and I’m within the 7 day return period. I am returning it.

Removed the heads off of my ‘69 Ford XL’s 302. Coolant was pooling in the rear two cylinders on each side. Intake and head gaskets didn’t look too bad. Lack of thread sealer on the bottom row of head bolts may have caused the coolant to get pulled into the cylinder. The bottom row of head bolts go through the water jacket, hence the need for thread sealer on them. Inspecting the heads, I noticed that the intake valve guide casting as seen through the intake to cylinder port are cracked and chipped on 5 cylinders. My question is, should I not use these heads at all? I didn’t find any pieces in any of the cylinders or anywhere else. I don’t know how long they have been like this but I don’t think it is part of the original problem. Heads were professionally rebuilt about 30 years ago.

My friend has this sitting around and didn’t know what was wrong with it, and I found out the belt was snapped. I replace the belt and now it sounds like this. The engine rattle a lot when I give it gas. It has no issues when idling. Sorry for not the best video. Just wondering if anyone where would have ideas of how to fix this.

Hello everyone. I picked up a bunch of what I believe to be 1966 Mustang parts, but I'm trying to positively ID one of the carbs. I can't find any major markings or logos. There aren't any tags. Maybe a number here or there. But I'm not 100%

I'm leaning towards Autolite 4100 or 4300. But I don't know.

Any help is appreciated. Thanks

Does anybody know what type of main jet this is? Can’t find it anywhere on the web. Its for a 50cc Keeway scooter (Keeway X-Blade 50cc 2018). Engine type: 1E40QMB-4. Carburetor brand is Leader.

Can anyone help me, currently my RPM at idle is 3,000-4000k I don’t know why. Idk what to miss with first my mix screws or my governed. I bent the tab on my plate and tried adjusting but it didn’t change anything.

Muarry 2003
Model: 425001X8
31c700 engine

I know the carburetors need tuning , but I don’t know if it’s running lean or rich and also on my gauge it says that one pistons only has 50 psi and the other has 100 which I don’t think it’s right because it reaches max RPMs please help

Thinking about buying this ranger on marketplace. Had it sent off for a PPI today and mechanic noted sound from engine. I’d have to pay another $200 for them to get in there and get a diagnosis. What do you guys think about the sound?

2002 2.3L inline 4

For context, engine got flooded, I emptied the water out by taking spark plugs out and removing the water, good news the engine will crank, but it won’t fully start up. The video above is what happens. Does anyone have any insight on it? I assumed it’s either smth with the ignition and or an electrical connection is corroded/rusted so it won’t fully spark.

Looking for some advice from people who know these engines better than I do.

I brought my boat in because it had a belt squeal while running, and the starter mounting bolt had snapped. The shop told me the engine was seized and needed to be replaced. They said the seized engine is what caused the starter bolt to break. I think they were too busy and didn't want to look at it.. but idk..

What I found confusing is that the engine had been running at the boat ramp just a few days earlier while I was trying to diagnose the belt squeal. It didn't seem like a completely seized engine.

For reference, it's a 2003 MerCruiser 3.0L.

Since I had pretty much written the boat off anyway, I decided to pull the engine apart as a learning experience rather than spend the money on a replacement.

After removing the head/valve train, I found that the crankshaft/pistons will rotate by hand. It turns fairly freely, but there is one spot in the rotation where the resistance noticeably increases slightly before it continues turning again.

My questions are:

• What could cause resistance at only one point in the crankshaft's rotation?
• If I'm already this far into the engine, is it worth replacing the rod/main bearings as preventative maintenance?
• Should I replace the piston rings even if the cylinder walls look good and I'm not planning on having the block machined or honed?

I'm not trying to build a perfect engine.. I mainly wanted to learn and see if I can get this one running again instead of scrapping it. Any advice is appreciated.

i have to do a test about engines including gas turbines and diesel/petrol and more… i found yt videos explaining them but i couldn’t find one that’s great at explaining gas turbines. will anybody please explain to me how a gas turbine works??(pls don’t use professional words since im just a korean student🥺

this piston has 50 hours on it, but not from racing just medium-paced riding. it’s from a 2022 KTM 125 sx, and i need honest opinions whether to change it or not.
thanks in advance for any help

Trying to figure out if this is the 2.0 or the 3.5

Hi everyone,

I'm trying to identify the engine on an older RC airplane that I recently got. Unfortunately, there aren't any obvious markings or model numbers that I can find, if u know where i can find more info, please comment.

If anyone recognizes the manufacturer or exact model, or even has a good guess, I'd really appreciate the help. If there are specific areas I should photograph (carburetor, exhaust, mounting lugs, backplate, etc.), let me know and I'll upload more pictures.

Thanks!