Help me diagnose this problem, need input.

[bsocko]

Ok here goes, new plugs gapped to .23, good spark on both engines, new optima blue top battery. Just replaced one engine, put break-in oil directly in the gas. Both engines have good compression on both cylinders which around 150 psi. Ran for 4 hours, ran great!

Both engines start great cold, once ran and hot, engines will sometimes not restart, one will, one won't etc.

I cleaned the fuel filters out already. Engines still have good spark but still dont restart when hot.

I never had this problem till i pulled out the other engine and put in the new one. Is the break in oil causing this? Do I have to purge a full line somewhere that I missed? The plugs are gas wet, when I take them out after the failed restart.

What is the problem here? Any idea's?

 

[stmanser]

Are your water passages lined up correctly ont he new engine?

could be over heating.

 

[bsocko]

I pulled the one carb on the right side of the boat, me and a friend rebuilt it. Turns out that part number 53 was stuck open with corrosion, is this my problem? What is this part, the pop off valve?

 

[cjb]

Thats the acceleration pump. I am not sure if it will cause flooding on the engine by just been stuck open.

You have to get a pop off tester. That is the only way to know if the carb is working correctly. Check out the link i sent you. There it explains what it is and how it looks like. Is just a manual pump with a gauge.

 

[bsocko]

Where do I get one at?

 

[bsocko]

will this work?

http://www.sears.com/shc/s/p_10153_12605_00947835000P?keyword=vaccum+pump

 

[pincusa]

No, that won't work as it's a vacuum pump. You want an air pump (think small bike pump)
There's a sticky on how to make one. I'd say try that

 

[Chester]

What is your rotary valve clearance?

Chester

 

[bsocko]

Both engines are doing this, including the brand new one, which have a NEW RV in it timed to 157. The old engine never did this till that damn SBT break-in oil i put in the gas.

 

[timmyboy76]

if timed at 157*, thats your problem. Needs to be 147* (probably mis-type on your part). The xcellerator pump, remove it, and go thru it, clear it out, and grease it up. If its not squirting at throttle hit, then it'll bog down. The carb/s are "jetted" to the xcellerator pump working properly.

 

[Chester]

Both engines are doing this, including the brand new one, which have a NEW RV in it timed to 157. The old engine never did this till that damn SBT break-in oil i put in the gas.

The break in oil will not affect it.

Chester

 

[bsocko]

That is a typo, should say 147. I am gonna do the pop off test now, and see what it tells me and i will report back.

 

[bsocko]

Ok, I did the pop off test, plugged the fuel out, it pops off around 45psi and drains down to about 36 psi and stops. Now what does this tell me?

 

[bsocko]

Update, even after the carb rebuild, the boat will wont start hot after you shut it off for longer than 5 minutes, any other idea's?

 

[seadoodude1]

A common reason for hard warm start is a leaking needle/seat in the carbs causing the engine to flood with too much fuel. If you pull the plugs when this occurs and crank engine you may find excess fuel spray out, then it will probably start.

 

[Chester]

Update, even after the carb rebuild, the boat will wont start hot after you shut it off for longer than 5 minutes, any other idea's?

Did you check your rotary valve clearance?

Chester