Problem with 3.0 liter Mercruiser

[moparmatt]

I have a 1988 sea sprite 17.5 bowrider i just got. I took it out for the first time sun and it ran ok for about a hour. Then all of a sudden it sounded like it was missing . I limped it back to the dock and got irratated. The guy i bought it from said the carb had been rebult. What should I look at first? Could it be something else?

 

[JustJason]

Re: Problem with 3.0 liter Mercruiser

Compression fuel and fire is what you need. If he rebuilt the carb, but there is no fuel/water seperating filter installed, then the carb could possibly be junked up again.

 

[antsmands]

Re: Problem with 3.0 liter Mercruiser

I have a 1988 sea sprite 17.5 bowrider i just got. I took it out for the first time sun and it ran ok for about a hour. Then all of a sudden it sounded like it was missing . I limped it back to the dock and got irratated. The guy i bought it from said the carb had been rebult. What should I look at first? Could it be something else?

Ah yes, a Sea Sprite; I have a 1986, 17.5 with a 3.0. These engines are quite good and not to difficult to work on. Start checking through the normal things that happen with engines of this age. Have you checked the oil to see if you have water in it. That could be a cracked block leaking into a cylinder and causing your miss. Check the cap, rotor, points and plugs, timing? All can cause a misfire situation. I put an pertronics electronic ignition on mine to do away with the points and it works great. Check the A/F mixture screw to see if it has been damaged during the rebuild. Maybe just rebuild it again yourself so you know it right. I rebuilt mine and it made a huge difference. Not too hard just tedious. Go through these an post back. There is plenty of help on this forum. Pic of the boat will help also.

Good Luck!

Tony D.

 

[MBAKER]

Re: Problem with 3.0 liter Mercruiser

If it has points/condenser setup, try changing the condenser. They are cheap and easy to do. We fought a similar problem one time with a brand new distributor, swapped in a used condenser and problem solved.

 

[moparmatt]

Re: Problem with 3.0 liter Mercruiser

All can cause a misfire situation. I put an pertronics electronic ignition on mine to do away with the points and it works great. Pic of the boat will help also.

Do you have a link to this electronic ignition setup?? Id love to get rid of the points. Here is a picture of the boat.

 

[moparmatt]

Re: Problem with 3.0 liter Mercruiser

Have you checked the oil to see if you have water in it. That could be a cracked block leaking into a cylinder and causing your miss.

If the block was cracked wouldnt the motor run hot after a hour of run time?

 

[tschmidty]

Re: Problem with 3.0 liter Mercruiser

Nice looking boat, If the block was cracked you would see water in the oil, which you would need to drain to see, or run it for a bit to mix the oil/water and check the dipstick. No, the motor would not necessarily run hot since it is an open water cooling system.

I'd run through ignition first to check the missing. Check the dwell, timing, wires, cap, condensor, and plugs. Get it running ok first before investing in an electronic ignition (pertronix or other).

 

[moparmatt]

Re: Problem with 3.0 liter Mercruiser

MANN do i hope the block isnt cracked

 

[moparmatt]

Re: Problem with 3.0 liter Mercruiser

Got the motor to run again today on the muffs. I put a can of Heet drygas in it. I changed the plugs and i let it run for a couple minutes. I checked the dipstick and i can see no sighns of water in the oil!! It does run but it runs pretty rough and when i rev it it sounds like its only on 3 cylinders Any ideas now??

 

[Aloysius]

Re: Problem with 3.0 liter Mercruiser

An individual miss cannot be the carburetor. More than likely it is secondary (high voltage) ignition. The cylinder missing will be cold on the exhaust/spark plug.

 

[Bt Doctur]

Re: Problem with 3.0 liter Mercruiser

When it starts missing, shut it off and pull the #4 plug, see if it`s wet or if water comes out the plug hole. Sign of a bad riser leaking into #4 exaust.

 

[chaparall villain 2]

Re: Problem with 3.0 liter Mercruiser

you mi8ght also try hotspark.com for electronic conversion ... i put one on a boat and its basically the same setup as petronix but alot cheaper and it screws right in where the points went so you need to change nothing in the distributor but take the points out and put this in and wire it .... i think its about 49.00 so alot cheaper and it works oh and also it comes with the pickup that slipd over the distributor shaft for the electronic system .... good luck

 

[moparmatt]

Re: Problem with 3.0 liter Mercruiser

SOmeone told me it could be the ignition coil going bad. Is that really possible? Can i put any 12v automotive coil on it just to try and see if that fixes it?