can't figure it out

**luv2gofast** · 08-10-2017, 08:05 PM

Originally Posted by rock

I should have explained it better. Main issue is it will not idle under 3000 nor pull past 3000. It's like it is stuck there.

Although it's strange that it won't rev up when you open the throttle if it's a vac leak. Does it sound like it's sucking air as you crack the butterflies?

**powerabout** · 08-10-2017, 09:50 PM

You might prove an airleak if you squirt fuel down a carb when you open the throttle

**90 5.0** · 08-10-2017, 11:09 PM

Have you checked all the bleed lines? I had one break up in the bundle behind the soliniod plate and do exactly that.

**NICE PAIR** · 08-10-2017, 11:23 PM

Back in time I had a 85 hp 4 banger that was loose enough it would need new crank seals every 2/3 years. It was on an old beater pontoon, when it started idling to fast to shift, i'd pull the powerhead @ the dock and throw some seals at it, put it back on next day. ran great, til some sob stole it

**bullet123** · 08-11-2017, 04:22 AM

**outasite** · 08-11-2017, 05:02 AM

If ya can keep it runnin long enough to spray some ether around the seam,it could help locate your leak.

**bullet123** · 08-11-2017, 06:01 AM

Is it possible upside down piston???

**rock** · 08-11-2017, 06:44 AM

Really appreciate everyones time and opinions. Guess I'm just trying to avoid the inevitable. Pulling it apart Saturday and I'll post results. The fact that it was a running motor had me convinced it was something I was missing.

Rock

**tlwjkw** · 08-11-2017, 06:54 AM

Originally Posted by rock

The fact that it was a running motor had me convinced it was something I was missing.

Rock

but was it runin' good or same way its runin' now?

**ssv1761982** · 08-11-2017, 08:08 AM

Originally Posted by rock

I should have explained it better. Main issue is it will not idle under 3000 nor pull past 3000. It's like it is stuck there. All linkages correct. Carbs off cam. It times fine and is set at 11 atdc and 18 btdc. Throttle plates completely closed. I thought air leak but have changed all gaskets. Fuel pump diaphragm good. Air silencer is off and fuel bowls are full. Checked enrichner and it is working correctly. I am running out of things to check. Last week I had one brought in that had a blown head gasket but they ran it anyway till the rods welded themselves to the crank. I put in a new sleeve, crank, and a couple rods and it started and idled instantly. It's not that I am a wizard or anything but it's not my first rodeo either. Absolutely dumbfounded. Thanks for the ideas.

Rock

I am surprised it will run at 11atdc. Is the timing pointer correct? Throttle blades shut at idle? (I know these are all basic but nothing else seemed to work)

**Capt.Insane-o** · 08-11-2017, 11:21 AM

I had a motor brought to me that was assembled without the sealing rings and it ran about the same way.

**Go Time** · 08-11-2017, 12:20 PM

Rock, before you tear it down, change the flywheel. Wonder if trigger magnet is moving....if not find the leak...
How smooth is it running at 3K. All cylinders seem even?

**transomstand** · 08-11-2017, 12:22 PM

Originally Posted by Go Time

Rock, before you tear it down, change the flywheel.

Think he's had 2 or 3 on it already.

**Go Time** · 08-11-2017, 12:29 PM

Yep, you're right...I missed that in the list ( it was pretty long)
Sneaky Leaky

**rock** · 08-11-2017, 07:08 PM

The kid I got it from is a good kid. Traded an STV for the rotating assembly and a new jack plate. STV needed some serious attention. He had it on his bass boat and said it ran well. All I got from him was a rotating assembly with a starter, coils, and carbs which were correct and spotless. It sat in my shop for about a year before I messed with it. Since I live in a barn I wouldn't be surprised at anything I may find but I did think it had an air leak from the beginning which is why I changed most of the gaskets. Guess I should have split case before mounting it on this guys boat. It will come of tomorrow and then I will know for sure what I have. Learn something every day and should have known better. Thanks again for every ones time, info and opinions.

Rock