1997 force 40hp issues

[Ribsyj]

Got my first boat this week. A 1999 crestliner pontoon. It has a 40hp force by mercury on it. So first time out on water it was running little rough had a slight studder. So opened cover up and checked plugs. Bottom plug was little milky white. Cleaned and reinstalled. But also noticed water in the bottom of cowl and oil residue in there. So started it up and seems water and exhaust coming into cowl. Also noticed water coming from coming from between cowl and lower unit running down driveshaft housing. Previous owner said shop told him exhaust seal was bad and need to remove lower to fix. Got great deal on boat now to try figure out where to start. Any help would be awesome

 

[Sumoldphart]

I'm gonna respond even though I'm a new boat owner and probably don't know what I'm talking about...and because no one else has. I just acquired a 40HP Force on a pontoon too. Mine's a 1995. Please preface all my comments below with "in my opinion"

The stutter is probably the carb having gunk in it from sitting. Mine did. I might try fresh gas with the right amount of oil and some seafoam before disassembling the carb.

The milky plug is likely water in the combustion chamber. I'm thinking head gasket but maybe the exhaust seal could cause that too.

Removing the lower unit is easy enough. I was told that smart Force owners replace the impeller on the water pump every other year so I did that and changed the lower unit oil. I found a couple Youtube videos on it and there were no surprises.

I'd get a service manual before going too far if you're going to keep the motor.

I'm still on the fence whether to run this one or find a bigger motor. Mine really works hard to maintain 12-13 mph and uses a lot of fuel in doing so. I'm thinking I may try and find a 60HP four stroke to replace it.

Good luck with yours.

 

[Ribsyj]

Did compression check an both cylinders hold about 125 Tore it down and found the adapter plate gasket blown

 

[Nickstoyz]

Hi, I have a 96 50 hp that had that exhaust problem. Hardest part is to get over the nerves of doing it! All the parts I found here in Iboats. And there is a lot of discussions about this topic. Just do a search of exhaust getting into cowl or something similar. My biggest expense was to buy a engine hoist. Found one on craigslist for 50 bucks. But you can pull the power head off any way you want. I also pulled the lower unit on mine. That made it very easy to pull the power head off. Do the exhaust fix then go after your studder.

 

[jerryjerry05]

You fix the stutter?