Lack of power/ surging 4.3 V6 mercruiser

[diggerdan17]

New to me 1998 bayliner capri 1850 SS with the mercruiser 4.3 190 HP V6

engine serial # 0L011173

drive serial # QL127614

Took it out to the lake today (ice finally came off!) and it seemed slightly under power when trying to plane . Then when up on plane it leveled out at 4200 rpm and about 40 MPH ( GPS) went through some rough water and it came to life and hit 4900 rpm (trimmed out) and was doing 47 MPH. Prop is 4 blade 22 pitch aluminum. Played around with full stop to wide open throttle for a bit and some times it would plane fast and hit 47 mph and other times it seemed gutless and only hit 40 mph.

I do have a spare fuel/ water separator filter that I can put on (which I will, and I'll dump contents into clear jar and let sit to check for water). Whats my next step to check after filter? Boat idles very nice at 600 rpm and shifts beautifully, no water in oil and it holds steady at 175 for temp , oil pressure is 30 psi at idle and 60-70 at WOT.

I am going to figure this out and will post back with the resolution so any body searching for similar issues will know what solved this.

Thanks

Digger

 

[diggerdan17]

Re: Lack of power/ surging 4.3 V6 mercruiser

May as well rebuild the carb I guess. Which carb kit should I order?

Took off fuel/water separator and it looked good( even cut open used filter) no water or sediment present. Fuel filter was only 7/8 full when I spun it off. I change oil and fuel filters on heavy equipment and always get soaked when removing filters.

 

[dubs283]

Re: Lack of power/ surging 4.3 V6 mercruiser

might just be some crud in the carb floating around causing intermittent issues, if you take apart the carb to clean it you may as well rebuild it

don't know which kit you need, don't know which carb you have

not a bad idea to check the fuel tank pick-up tube, seen lots of junk clog those from time to time

fuel pump pressure/vaccuum test is a good one too

 

[diggerdan17]

Re: Lack of power/ surging 4.3 V6 mercruiser

might just be some crud in the carb floating around causing intermittent issues, if you take apart the carb to clean it you may as well rebuild it

don't know which kit you need, don't know which carb you have

not a bad idea to check the fuel tank pick-up tube, seen lots of junk clog those from time to time

fuel pump pressure/vaccuum test is a good one too

Its a 2 barrel, but I'm just guessing that its a mercarb? Going to pull it off tonight after work.

 

[diggerdan17]

Re: Lack of power/ surging 4.3 V6 mercruiser

Ok, so new fuel filter, cleaned carb , new plugs, plug wires, distributor cap and rotor.

No more issues, runs like a top, plenty of power out of the hole and decent top end speed,

Not sure which item needed attention( one of the spark plug wires had a rip in the boot right down to the metal, could have been arcing out and only running on 5 cylinders) but it's nice to have a fresh tune up for piece of mind.

Bring on the summer heat!!

 

[MikDee]

Re: Lack of power/ surging 4.3 V6 mercruiser

An erratic spark at the plug would definitely do that, sounds like you solved your own problem!