Few questions 5.0 mercruiser

[Nscarman]

Hello all, newbie here that has found alot of useful info here! Thank you all for the help! Now here goes, i bought a 90 rinker v 186, orginally had a 4.3 i/o and the people i bought it from put a 5.7 in it. Well marina told me motor had water in it so i found a 5.0 volvo penta so i swapped everything over, new coupler, all new bellows, new gimbal bearing. Put a mech fuel pump(auto-in process of buying a marine one). Finally had it on water sunday, ran decent, first test has smoke coming from the little breather cap in valve cover and blew the dipstick out of the tube. This was a makeshift dipstick and tube as there is very little clearance from the bottom of exhaust manifold. Stuck a hose and bolt and clamped them in, ran it again, ran good but not sure what to do next. It has a 2bbl rochester(i think) carb with a hose out of the back of it at the bottom that is pulling a vacuum from, stuck bolt in it til i hear what to do next. Been told everything from bad motor, worn rings, cranckcase needs a vent. Trying to figure out best way to fix whatever else is wrong. Would appreciate if any of you guys could give me some ideas. Thanks

 

[biggjimm]

Welcome, these guys around here can solve pretty much anything. Once they're given enough of the right information, that is.
In my experience if the pcv valve (positive crankcase ventilation) is bad or there isn't one & no where for that pressure to vent, it will build up & can definitely blow the dipstick out. If the rings are bad that'll show up in a compression check, which, if you haven't done already, you should, just to know the health of your engine if nothing else. Also if the rings are bad, you should be able to smell gasoline in the oil on the dipstick. Which if severe enough will thin out your oil & can trash your bearings. Some of the "smart guys" will be along shortly & offer up some ideas as well.

 

[thumpar]

Boats don't have PCVs. They are open in the elbow. Do a compression check.

 

[Nscarman]

Will start with a compression test this weekend. Thumpar-what do you mean they are open in the elbow?

 

[biggjimm]

Boats don't have PCVs. They are open in the elbow. Do a compression check.

You are absolutely right. I thought mine had one but when I checked it, it was hollow.
Nscarman, I think, & I very well may be wrong, & if so thumpar will tell us but mine looks just like a pcv valve but it is empty. It is just a hollow elbow & I think that might be what he meant.

 

[NHGuy]

First off, welcome to the forum!
The top valve cover outlets are open to atmosphere. Put some plastic elbows there and lead them into flex hoses. The hoses terminate at the air intake where the crankcase gases will then get pulled into the carb. If you have the old engine, it should have the bits.
You will need some kind of dipstick so work that out.
You can also get the marine fuel pump off the other motor.

Safety item. Use marine electrics, and fuel stuff. The distributor, alternator, fuel pump and carburetor must be marine.
The pump and carb have a linking tygon tube to catch and show any fuel that gets past the pump diaphragm. The carb has a vacuum port for the tube. If the tube gets gas in it you know to replace the pump. Us old guys would call it a telltale.
The electric stuff is shielded so it won't spark.
These things are designed to eliminate fuel vapors and sparks in your engine compartment. The reason it's different from auto is that in cars and trucks the vapors just go out under the car. But in boats they would just sit there.

 

[Nscarman]

Man you guys know your stuff!! Im not sure about the elbows, this thing had chrome edelbrock valve coverson it(i swapped them from the old motor) but only holes in it is a cap on the starboard side and a round breather on the other. Heck they may not even be the right thing. Everything else the prior owners have done has had to be redone. I have a compression kit coming so i will do that this weekend and post results. Again guys thanks for all your help!! I may get to play with it before winter is upon us! Living in ohio doesnt give for a long season!

 

[biggjimm]

What NHguy said about the non marine parts above. Get them off of your boat! All they are good for is turning a boat into a bomb.

 

[81 Checkmate]

Just to add - May want to check on the carb to make sure it's not an auto carb. The reason i say this you commented on the pluging the hose. Useely do not see vacum hoses on a boat carb.... May be able to use the carb off the volvo motor?

 

[Nscarman]

Ok guys, went and did some checking, the old stock valve covers have to holes for a hose or tube to go inside them, i am assuming they would run to the spark arrester. And the 2bbl carb that is on it, i got the numbers off it, 861448. And 9401. I also have a quadrajet that came off the old motor that i an thinking of rebuilding it and replacing the 2bbl.