PCV valve troubles

[pontosquantos]

I have a1986 Rinker fiesta vee 250 with a mercruiser 260, cannot locate serial #. alpha one se106 leg. this is a close water cooled. it wasn't running good at after the first run of the season, so I started to change the standard parts. this is what has been done so far:
rebuilt Rochester quadrajet carburetor, new plugs, wires, coil, distributor cap, rotor, fuel pump, carburetor anti- siphon valve and PCV valve. boat still won't reach wide open throttle. it will max out at about 2800 rpm under load. I can reach 4800 rpm in neutral .figured maybe blocked exhaust possibly lodged a flapper. Checked them and they are fine. figure that I will run out the season cruising at low speed, (not a biggie saves fuel..) I will go over it better in the winter when i have it out of the water. I went on a four hour trip last weekend and the boat ran great chugging along 1500rpm. on my way back the boat stalled as if the ignition was shut off. I pulled the hatch and could see that the back of the intake manifold was covered in oil. I didn't bother to try a restart, just limped back in on my kicker. Seems to me that my PCV valve failed and over pressured the crank case. once I started to investigate I discovered that when the mechanics replaced my electric fuel pump with a mechanical pump, they took the hose for my PCV valve and moved it from the intake manifold to the flame arrestor. they put a plug in the manifold where the hose went to before. when I look at this it does not seem right, there is a PCV valve on one valve cover attached to the flame arrestor and no breather on the other valve cover. how would this work? should there be a breather on the other valve cover? and would this cause me to not get the rpm's I am looking for?
thanks for your advise in advance

 

[thumpar]

You shouldn't have a PCV valve in an older carb motor. It should just be a breather tube.

 

[Fishermark]

You should not have a PCV valve. It is an empty shell. And yes the hose typically is attached to the flame arrester. Could you tell where the oil was coming from? A leak, or blow-by? If blow-by, then it is time for a compression and leak down test.

 

[Bt Doctur]

with a mech pump you must have the "tell-tale" hose running from the pump to the flame arrestor. As far as the pvc, is hollow inside and is not connected to manifold vacumn. just plugs into the valve cover and directs any fumes to the flame arrestor.

 

[Bondo]

I have a1986 Rinker fiesta vee 250 with a mercruiser 260, cannot locate serial #. alpha one se106 leg. this is a close water cooled. it wasn't running good at after the first run of the season, so I started to change the standard parts. this is what has been done so far:
rebuilt Rochester quadrajet carburetor, new plugs, wires, coil, distributor cap, rotor, fuel pump, carburetor anti- siphon valve and PCV valve. boat still won't reach wide open throttle. it will max out at about 2800 rpm under load. I can reach 4800 rpm in neutral .figured maybe blocked exhaust possibly lodged a flapper. Checked them and they are fine. figure that I will run out the season cruising at low speed, (not a biggie saves fuel..) I will go over it better in the winter when i have it out of the water. I went on a four hour trip last weekend and the boat ran great chugging along 1500rpm. on my way back the boat stalled as if the ignition was shut off. I pulled the hatch and could see that the back of the intake manifold was covered in oil. I didn't bother to try a restart, just limped back in on my kicker. Seems to me that my PCV valve failed and over pressured the crank case. once I started to investigate I discovered that when the mechanics replaced my electric fuel pump with a mechanical pump, they took the hose for my PCV valve and moved it from the intake manifold to the flame arrestor. they put a plug in the manifold where the hose went to before. when I look at this it does not seem right, there is a PCV valve on one valve cover attached to the flame arrestor and no breather on the other valve cover. how would this work? should there be a breather on the other valve cover? and would this cause me to not get the rpm's I am looking for?
thanks for your advise in advance

Ayuh,..... Welcome Aboard,...... Read This,.....

It's found in Don'S Adults Only section at the top of this forum,....

Is this a dock boat, or trailer boat,..??

Have ya done a Compression, 'n leak-down tests,..??

 

[pontosquantos]

thanks for the response. there is a hose that goes from the base of the carburetor to the mechanical fuel pump, but not to the arrestor. this Is a docked boat. I am going down on Saturday to clean up the oil and see if I can spot where it is coming from. I will also pull the plugs and do a compression test. I will post the results when it is done. I will replace the pcv valve with a breather cap. do I need a breather cap on both valve covers?
thanks again for all your help.

 

[Bondo]

thanks for the response. there is a hose that goes from the base of the carburetor to the mechanical fuel pump, but not to the arrestor. this Is a docked boat. I am going down on Saturday to clean up the oil and see if I can spot where it is coming from. I will also pull the plugs and do a compression test. I will post the results when it is done. I will replace the pcv valve with a breather cap. do I need a breather cap on both valve covers?
thanks again for all your help.

Ayuh,.... Ya don't need breather caps, ya need a simple elbow from each valve cover, to a simple plastic hose, to the edge of the flame arrester,....

 

[Bt Doctur]

pull the hose off the fuel pump, start the engine and check for vacuum on the hose. there should not be any.If there is, remove the hose from the carb and plug the opening. a giant vacuum leak will kill the performance

 

[pontosquantos]

ok sorry it took me awhile to update, been quite busy of late.I found that my intake manifold was the cause of the oil leak. re did the intake gasket, no leaks ya! checked the compression all within 150 to 140. reset timing 8'tdc. go for a test drive and now i cant get anymore than 2500 rpm. tried to advance the timing while running under load still no more rpm's. I could turn the distributor advance a long way over a 1/4 turn wihout any clacking? it almost feels like the engine is on a govenor. not sure what to do next :facepalm:

 

[Bt Doctur]

need to see some pics of the carb, fuel pump, small hose from the mech pump to where it connects at the carb.
You need to check the firing order of the plug wires,1.8.4.3.6.5.7.2 clockwise Cylinders are numbered 1,3,5,7 port side . 2,4,6,8 stbd side
No hoses from the manifold to the valve covers. you should find 2 vent hoses from the valve covers to the flame arrestor

 

[pontosquantos]

OK went to the boat yesterday and of coarse forgot my camera. I have replaced the PCV valve with elbows from each valve cover with hoses that connect to the flame arrestor. I made sure to re-check the firing order again, which is correct. the hose that goes from the mechanical fuel pump is attached to the barbed fitting in the picture of carburetor .


Went out for a test drive and still the same no more than 2500 RPM... at a loss as to what next...

 

[thumpar]

You should have 2 lines from the fuel pump to the carb. One solid and the other one is clear. Does the clear line have fuel in it? If so you need a new fuel pump because the diaphragm is ruptured.

 

[pontosquantos]

Yes i have a braided steel fuel line from my fuel separator to the carb, and the clear hose has no fuel in it. it is a brand new fuel pump that replaced the old electric one. I am starting to think that i bought a lemon

 

[pontosquantos]

Went down to the boat again and decided to pull the spark plugs and see if that could tell me what is going on. not to sure how to read them.

1,3,5,7

2,4,6,8
these plugs where new and have run for about 2hrs.
Thanks,any advise would be appreciated

 

[Fishermark]

Yes i have a braided steel fuel line from my fuel separator to the carb, and the clear hose has no fuel in it. it is a brand new fuel pump that replaced the old electric one. I am starting to think that i bought a lemon

The fuel should go from the tank to the separator - then to the pump - then to the carb. Don't know if that is your problem or not, but the separator needs to be before the pump.

 

[Fishermark]

The plug on #2 looks mighty clean. Steam cleaned perhaps? That would mean water is getting in that cylinder. You have a mixed bag of plugs. Most look like they have been run rich... with one looking good and one looking too clean.

 

[pontosquantos]

This is starting to make sense now after I redid the intake manifold gasket and added the coolant back into the system I noticed that the coolant kept on overflowing out of the heat exchanger while the motor was running. What I thought that this was just an air bubble in the system is probable pressure from a leak. I am guessing now that even though it doesn't show the more obvious symptoms like overheating, coolant in the oil and white smoke from the exhaust, that it is a blown head gasket? would this also explain why my vacuum reading was 15 hg and fluxuating -3 hg rapidly?

 

[NHGuy]

Yes, white smoke and coolant in the oil is very likely a head gasket. if it's just coolant and oil mixed you have a heat exchanger problem. Do a coolant pressure test, compression test and leakdown test to further prove the issue.