3.0 L Mercruiser Questions

[Sonofasailor]

I am new to this forum. I live in Saskatchewan Canada. I have owned my 99 Bayliner 175 Capri for 5 years. It has a 3.0 L Alpha One drive. I love the boat.

I accidently overfilled the crankcase with oil last fall when I winterized the boat. The resulting symptom seems be a loss of top end speed. With a 14 x 19 prop @ wot I am getting about 36 mph. Last year @ wot I was getting about 42 mph. I could not tell you what rpm's I am running as my tach is all over the place, what causes that? The motor starts and runs well once warmed up sufficiently. it almost seems that at wot there is a slight miss, fuel issue? How does one change the fuel filter?I just noticed last night that I had a slight film of oil (I think) on top of the valve cover by the pcv. Should I replace the pcv?

I really hope my stupidity hasn't wrecked anything!

I am open to any positive thoughts or suggestions.

 

[IES99]

Re: 3.0 L Mercruiser Questions

I doubt that the overfill (by how much may I ask?) has caused much problem if you have gotten it filled correctly now. Do you have fresh fuel? A water separating fuel filter?

 

[Sonofasailor]

Re: 3.0 L Mercruiser Questions

I drained out about 3/4 of a litre of oil out of the crankcase.

The boat was stored full of gas with fuel stabilzer in it. Starts great???

Does the 3.0 L come factory with a water/fuel seperator?

Is the 3.0 fuel injected or carbuerated?

 

[Susquehanna Squid]

Re: 3.0 L Mercruiser Questions

I too doubt that the problem stems from the overfilling of the oil. I would run some dry gas and Seafoam through it and see if that fixes the problem. Also, just a thought, have you gained a substantial amount of weight over the winter? HA

 

[IES99]

Re: 3.0 L Mercruiser Questions

I drained out about 3/4 of a litre of oil out of the crankcase.

The boat was stored full of gas with fuel stabilzer in it. Starts great???

Does the 3.0 L come factory with a water/fuel seperator?

Is the 3.0 fuel injected or carbuerated?

As far as I know the 3.0 or boat does not come with the water separating fuel filter. Is your engine carbureted? I ask because if it is injected, you may need a specific type of water/fuel filter.

Mine is carbed (1988) so the fuel pump is on the engine and I have the water/fuel filter in the line between the tank and fuel pump.

 

[Sonofasailor]

Re: 3.0 L Mercruiser Questions

Thanks for the input. Haven't gained any weight over the winter.

I think it is carbed?

I'm scared to ask, but what is drygas & seafoam?

 

[fat fanny]

Re: 3.0 L Mercruiser Questions

Seafoam is a liquid treatment that has been around for years and does help with numerous fuel and slight mis issues just add it to your fuel tank or to a seperate fuel tank supply and let it run through the system. But go to the top of this forum in the stickies and with all your motors info (size,serial#, year and make)and down load you servise manual if there still available! for free also check out the other usefull info in thestickies for the related issues your having but in all likelyhood your probably looking at a carb rebuid if so do a search on carbs for a 3.0 and you'll find all kinds of info here but start with the basics electrical,spark,fuel system,and compression carbs most likely it! Good luck!

 

[cooter2506]

Re: 3.0 L Mercruiser Questions

An over filled crankcase WILL cause your symptons. It airrates the lifters. BUT 3/4 litre may or may not be enough to cause it. Have you run it since you got that oil out? Your engine is carbed( I dont think they injected the 3.0). Drygas is basicaly a water absorber for your fuel. Seafoam is basically a varnish remover or a carb cleaner. As far as your tach jumping. Remove the wires to it and clean up the conections. Dirty connections cause tach jumping. 3.0 didnt come with a factory installed water seperator. But you can add one and I recommend that.

 

[ken_23434]

Re: 3.0 L Mercruiser Questions

I am pretty certain there is a Fuel Injected 3.0. I am sure I have seen schematics for it and such. Then again, maybe I was just dreaming...

I think everyone is assuming you did not run the motor over filled with oil.

If you run an engine with too much oil, the crank will contact the oil in the oil pan. The crank spinning really fast and smacking the oil will rob the engine of horsepower. The faster the engine is running, the more power it will rob.

The really bad thing, is that the fast spinning crank will churn up the oil and cause it to foam up. If it really gets churned up a lot, your entire oil system will be foamy oil, which will cause the oil pump to cavitate, which will lead to loss of lubrication etc...

Hopefully, you have verified with the dipstick that the oil is at the proper level after draining some of the oil.

Even if you filled the engine to the top of the valve covers with oil, stored the engine, and then drained it back down to the proper lever before running the motor, there is no chance of doing any harm to the engine. However, running the motor over filled with oil, could possibly lead to some problems.