115 hp merc. idols great,can't accel. over 10 mph

[Parkerj1]

Hey guys, I need help. I have a 1982, 115 hp Merc. It's sat in the previous owners garge for two years. He said the last time he had it out it was running good then all the sudden it bogged down to 10 mph and he couldn't get it to go any faster.
I bought it, got it home, drained the 10 gal. of gas left in the tank and replaced the prime bulb the hose and put an inline filter on.
We took it out the other day to see if that would fix it without having to clean out the carbs. Well it didn't.
It's back in my garge, I took the carbs off and completly disassembled them, cleaning every pin, needle and orfus on them. I just looking for other opinions on what to do if this dosen't solve the problem. Please help...

 

[Chris1956]

Re: 115 hp merc. idols great,can't accel. over 10 mph

Take a compression test. If the compression is good, the carbs are cleaned and properly adjusted, and it won't go, the ign system is next to check.

 

[Parkerj1]

Re: 115 hp merc. idols great,can't accel. over 10 mph

Chris1956, thanks for the reply. I have to wait until tommorro to see if cleaning the carbs solved the problem or not, because when I was taking the top carb apart I snaped the treads off a 90 degree hose fitting that ran from the bowl to the enrichener valve. But I can fix that.
I was just wondering how to do a compresion test, and if needed, what do I need to do to test the ign system?
Another thing, do you think it could have anything to with the fuel pump?
If so do I go about testing it?
Thanks again.

 

[Chris1956]

Re: 115 hp merc. idols great,can't accel. over 10 mph

To take a compresion test, remove all spark plugs. Install the compression gauge onto the top cylinder. Now jumper the starter solenoid (ign key off) to make the motor crank. Note the highest reading. Now repeat with the other cylinders. Compression should be 100+PSI and within 15% of each other.

Rebuild the fuel pump. The rebuild kits are real cheap.

the ign system on that motor has a high speed stator winding, as well as a low speed winding. You need to test with clean carbs and good fuel delivery to see if you need to ohm out the stator. Dolphinmarineservices.com has a troubleshooting procedure fro that ign system.

 

[Parkerj1]

Re: 115 hp merc. idols great,can't accel. over 10 mph

Chris thanks again. I'm going to get the fitting I need right now then I'll get her back together. I'll run those test and let you know what I find out...
Thanks again.

 

[Parkerj1]

Re: 115 hp merc. idols great,can't accel. over 10 mph

Hey, I got it all back together last night and put the water muffs on. I got it started in the driveway, it seemed to run and get up to full rpms just fine. I took it out to lake the to run it but it did the same thing it did before. It will get up to 2200-2400 rpms and then starts to bogg or stall at that point.
Do you think that sounds like the high end of the stator?

 

[Chris1956]

Re: 115 hp merc. idols great,can't accel. over 10 mph

It could be the high speed windings on the stator, or the motor could be overpropped.

 

[Mark Nagel]

Re: 115 hp merc. idols great,can't accel. over 10 mph

Background:
OK, for a background for future searchers. I have a 83' Mariner that was stored for a few years. When I took it out of storage it started and idled fine, reved up with no load, but in the water under load it would almost die, not getting the boat past 5 mph.

What I did:
I drained and replaced the gas and fuel lines.
Rebuilt the Carbs ($70 kits)
Checked the Baffle plate and water jacket and replaced the gaskets ($25)
Replaced the stator and rectifier ($220)
Tested all the electronics I could
Still no luck

What fixed it
On my year a few others, there is a idle stabilizer (mounted to the front plate in front of the carbs. It has 3 wires, ground, red/white and black/white. They hook into the lower switch box (Bias that connects the two switch boxes and the red from the stator). It advances the timing at idle when the motor loads up. Apparently it was scrapped due to issues and the motor doesn't need it to run, but if its faulty it wreaks havoc on your timing. The test is simple, disconnect it. If it solves the problem leave it disconnected. Its $170 and they told me not to waste my money, its not needed.

The carbs and gaskets were cheap and probably needed anyway, but I wish I knew this simple test before I bought the stator and rectifier. I hope this helps someone in the future.

Mark