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3.0 with no power

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benmorrison

Member
hi there guys, ive got a bit of a problem. i have an '88 bayliner capri (19') with a 3.0 paired to a cobra drive. my problem is the engine has no power what-so-ever.had it out a couple of times last summer and it went -ok- but could tell it wasnt performing correctly. this year, changed points, plugs wires cap n rotor, and it runs real good on the trailer. however.. once in the water it falls on its face, cant get over 2000 rpm's. i just ordered a carb kit and a new fuel pump but im not sure if that will fix it.
want to check the compression, what #'s should i be looking for? im realy only familiar with deisel #'s when it comes to that. also this motor doesnt have a harmonic balancer on it, so no timing marks, how do you go about putting a light on it for true timing? so far ive only been able to time it by ear (not very good results) any ideas would be greatly appreciated
 
all 3.0's have harmonic balancers. Maybe you have a 2.5, which would certainly lack power in a 19'

you changed points without a timing light? how?

I would check 5 things in this order for a 3.0 or 2.5 with low power:
1. Flame arrester atop carb - clean it (especially if this was a gradual loss of power)
2. change the fuel filter
3. have a look at the anti-siphon fitting where the fuel line connects to the tank.
4. look for exhaust shutter that has rotted off and is blocking exhaust outlet in drive
5. stuck/rusted advance weights and springs in the distributor
 
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hey guys, hystat, i checked all of the above without finding anything wrong. i guess the next thing would be how to time this thing. i had assumed it was a 3.0 because thats what it says on the valve cover. (obviosly it has been replaced by a previous owner)
cheif, i know u are a firm believer in compression tests so today i did just that. first on a cold engine and then as u had instructed. the warm test gave me between 120 and 125 on all 4. is this about where it should be?
one more thing, what plugs do u recomend for this engine? i dont think the ones i put in are hot enough but they were the only ones i could get at the time, thought they were ok but when i took them out they were fouled pretty bad
 
one more thing i just thought of, the ESA does NOT work on this boat, when i unplug it nothing changes, but could this be part of the problem?
 
that motor has to be a 3.0 they did not match a cobra drive with a 2.5. Maybe the motor was changed out . You say it has 3.0 on the cover and not 2.3. Thats a ford.

Anyway i know the 3.0 i have it in my boat now and had a 2.5 before that in the same boat 86' also a 19'

Let me ask a few questions if it's ok with you,

Did you check for water in the boat hull. My friend has a 92 bayliner and we drilled holes in the deck in the cabin and found hidden water. every gallon is 7 pounds.

What prop you have on the boat ?

the compression numbers are ok

Ok unplug the esa both of the plugs, run it on the water. I had the same problem when i got my boat took me 3 trips on the water till i unplugged them it was like night and day.

You might have to shut the motor off to come out of gear but then for sure we will know its the esa. Then we can go from there.

Keep us posted all the guys here will help to get you running right

Good luck
 
Chief...actually in 1986 (first year of the Cobra) they had the 2.5 and then changed to the 2.3 from 87 to 90. Being the boat is an 88 it should have the 3.0 (very popular for Bayliner back then) but who knows what a PO might have done?
 
yeah< it definatly has been changed, on the boat it says 3.0 as does the valve cover but the engine has definatly been swapped. just noticed that on the lifter cover it says mercruiser so i dont know what the heck is goin on. will the casting numbers tell me anything? still havent figured out what i need to run for plugs. i saw in a different thread that a 3.0 should take either a rv8c or mr43t but they wont fit in the head on my motor, the treaded portion isnt long enough to reach the threads in the head. the plugs i have in it are an ngk br8es but im certain they are not hot enough, just was the only thing i could find to fit in the darn thing. any thoughts?
 
pull the valve cover the date will be on the head. Got me stumped on the plugs same mr43t from the 70's to today on the 3.0 doesn't matter merc. or whatever other make.

Block should also have a date also
 
hey guys, rebuilt the carb and found some hotter plugs that fit the head, made a huge difference. however, i realized that i dont know jack squat about driving boats. took it out yesterday and was running better but not much power. thinking i needed more garage time with it i was on my way in when it dawned on me that i should try adjusting the trim and what do ya know.. darn thing took off like a bullet. imagine that:) had it running about 4000rpms at just under 40 mph. a big change from what i had previously ran. thanks for all your input, i have learned alot from reading other threads, u guys know ur stuff!
 
so you took off with the trim up? How did you see over the bow? Trim it down to take off, once it comes up to plane trim it up a little at a time, see what difference it makes. Dont trim it up all the way and run it, hard on the ujoints
 
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