Force 50 HP Problem

[kenny26]

Went away for the weekend and took the boat. Day 1 (stupid me) had the battery connections reversed and the boat was cranking but the starter wouldn't engage. After about 5 minutes, i figured that out and the boat started right up and ran fine.

Day 2 we ran to the other side of the lake and the motor ran fine. In the afternoon we headed to a restaurant across the lake and the motor couldn't get us on plane and there was small amounts of white smoke coming from it. On the way back, the motor again seemed to run fine until i throttled down to enter the marina at which point it shutdown completely and would restart but only run on 1 cylinder it seemed and would die when i shifted into gear. After several attempts it would no longer even run at all. Got towed into my slip and towed the boat home. I changed spark plugs, but still won't start. It seems the top cylinder is firing, but the bottom cylinder won't.

Any idea's. I'm going to check compression and spark on the bottom cylinder but haven't gotten to it yet. I'm feeling like this is an electrical problem though I may be wrong.

Any ideas what caused the white smoke?

Could reversing the battery polarity intially have caused the issue?

 

[olsenk514]

Re: Force 50 HP Problem

Sounds like you have a blown head gasket. Check the spark plugs and cylinders for signs of water. A blown head gasket will make it difficult or impossible to start, and it will run much slower. White smoke coming out may actually be steam, which is water getting in the cylinders. It's not hard to pull the head off and replace the gasket. If you're mechanically inclined it'll cost you about $30

Good luck

 

[kenny26]

Re: Force 50 HP Problem

Sounds like you have a blown head gasket. Check the spark plugs and cylinders for signs of water. A blown head gasket will make it difficult or impossible to start, and it will run much slower. White smoke coming out may actually be steam, which is water getting in the cylinders. It's not hard to pull the head off and replace the gasket. If you're mechanically inclined it'll cost you about $30

Good luck

Whats the best way to check for water in the cylinders, is there anyway to confirm the head gasket is blown? Compression test?
What causes the head gasket to blow?

 

[roscoe]

Re: Force 50 HP Problem

Reversing the battery cables most likely blew the voltage rectifier.
Running it afterwards, may have damaged the cd module.
Hopefully the damage stopped there, and did not damage the stator.

Time to thoroughly test the ignition system.

 

[kenny26]

Re: Force 50 HP Problem

ok. So i went out and checked, and I have a blue hot spark on both cylinders using a spark tester. I have 130+ compression on the top cylinder and bottom cylinder has only 40 PSI. I assume the compression is the problem... How do I fix that?

 

[olsenk514]

Re: Force 50 HP Problem

You should pull the spark plugs and compare them. If the one with low compression is clean you most likely have water getting in that cylinder (from a leaking head gasket). The easiest way to be sure is to pull the head off the back and inspect/replace the head gasket. I believe there's 10 bolts holding the head on and it should pull right off. Once it's off you can inspect the cylinders as well.

Kevin

 

[roscoe]

Re: Force 50 HP Problem

given that the gasket is indeed blown, you also need to find what caused it.
Is there sufficient water flowing thru the motor to prevent overheating?

Also, after you get it running again, check the voltage across the battery terminals while running. Should be 14+volts.

 

[kenny26]

Re: Force 50 HP Problem

Lower piston has chip out of it. Ugh.

 

[olsenk514]

Re: Force 50 HP Problem

Chip? Like a burn hole? Or a chip in the ring? I take it you pulled the head off?

 

[kenny26]

Re: Force 50 HP Problem

Not sure about the terminology, but when you look at the top of the piston its not completely round anymore there is a small chip out of it. Also when you look behind that I can see some material that looks like it has cracked.