85 hp Force extremely hard starting

Hello All,
I just got back from a great week on a house boat on Dale Hollow Lake in TN. The only stressful part was the pain in the butt my Bass boat was giving me. The darn thing was very hard starting. I had recently replaced the stator and it seemed to be fine but now every time I start the boat cold or warm I have to keep playing with the choke. I get the motor to kick with the choke on then again with it off, I am getting a cough out the exhaust if it does not take. Once the boat is started it I am getting about 4800 rpm at WOT and it was running smooth. On the last day it was even harder starting and even once it was started at WOT it ran ok but idling back to the marina it kept wanting to cough and almost stall, I would rev it back up and it would be ok for a short time then cough again. Luckily when it did cough and stall I was almost on the trailer. One thing I did notice everytime we stopped to fish and I checked the ball it was not very hard and I would pump it again. Any thoughts on what would be causing this would be helpful.

Thanks
MikeG

Re: 85 hp Force extremely hard starting

Do a compression test and post the results.J

Re: 85 hp Force extremely hard starting

J.
The compression check is as follows - 1 = 125, 2 = 100, 3 = 125.

MikeG

Re: 85 hp Force extremely hard starting

Comp is low in the center cyl.It can make it hard to start and hard to idle. Use Mercs Power Tune or Seafoam and try to bring the comp up.
There is a reason the cylinder is messing up.If you can't get it to come up then you might need to remove the head and check for damages,usually if the comp is that high it just needs to be de-carboned.
See if anything has gotten into the reeds or is stuck in the carb.
Re-set the air screws..J

Re: 85 hp Force extremely hard starting

is this problem like a backfire or just a slight stutter? Since you just changed the stator, you might want to re check to make sure you don't have a wire rubbing or something similar.By all means I'm not saying that the compression values are correct, but if its backfiring that means its either not firing at the right time ,or may have part of a piston MIA at the exhaust port side to change the closing time of the port a few degrees. Just something to think about.

Re: 85 hp Force extremely hard starting

was the flywheel nut properly torqued when the stator was changed?
remove it, check the key, replace the nut and torque, then check timing.

Re: 85 hp Force extremely hard starting

Make sure your timing and carb sync are correct.

If the timing is slightly retarded, someone may have turned in the idle screw to get a good idle. When you do this, the throttle plate opens and fuel from the main metering system can be pulled in with the fuel from the idle system. This makes for hard starting as the engine is getting too much fuel, especially when choked.

John

Re: 85 hp Force extremely hard starting

John,
That is very interesting. After replacing the stator I did not check the timing but I did mess with the idle adjustment. When I get home today I am going to try to check the timing before I go further.

MikeG

Re: 85 hp Force extremely hard starting

The timing and carb linkage is interrelated and you can't adjust one without checking the other.

Another instance of when idle screws get turned in is when performance drops off after the engine starts building carbon and rings start sticking. In this case, a good decarb will usually bring the engine back to normal operating limits but, with the idle turned in, the engine will start hard and slam into gear.

John

Re: 85 hp Force extremely hard starting

John,
I did check the timing and it was off, not by alot probably only about 5 deg. I got it back in line and wow what a difference. The starting problem seems to have been solved. I have it idling about 800 rpm and still need to take it to the lake to test the WOT performance. While I am in the mode I will do a decarb and change the fuel pump diaphram, I had it apart and noticed it was damp on the back side. I will keep you posted on the lake test when complete.

Thanks again everyone for all your help and input.
MikeG

Re: 85 hp Force extremely hard starting

Well I finally made it back out to the lake yesterday for one last time and the boat ran GREAT. The timing fixed the problems I was having. I will keep an eye on the compression readings and if they seem to fall off I will pull the head off and get into that. Thanks everyone again for all your help this has been one of the most helpfull and friendly sites I have ever participated in.

MikeG

Re: 85 hp Force extremely hard starting

Still do the power tune or seafoam.If there is carbon in there it will only get worse and cause damage.J