First run 120hp Force issues

[PaulO]

Ran the engine today in the river.

It is surprising the amount of water it was spitting out compared to the muffs. I am happy about that. It ran cool too...approx 80? F. Someone correct me if this sounds too cool?

ISSUES:
1. The tachometer runs upto 2500 RPM but no further. GPS says 67Kmh with a 19P x 13? prop 5.2metre fibreglass runabout.

2. Because I am running at 25:1 oil mix and the smoke runs up past exhaust rubber into cowling, when the cowl is in place it soon cuts out because the engine is ingesting carbon monoxide.

3. I bought a Rectifier/Regulator as per the sticky. It is only showing 11.5 volts on the volt meter that runs from the fwd controls ignition harness. It did increase from a lower figure so something is going on. A navman connected direct to battery shows 12.7 volts at cruise. I put a ammeter in but it doesn't seem to move. I connected it to the rec/reg pos and c/breaker to the + of gauge and the - to the battery side of the starter solenoid. No movement when cranking.

 

[jerryjerry05]

Re: First run 120hp Force issues

Sounds like it's cooling OK.Need to know what year motor?
You need to do a compression test and a spark test.Then check the diaphram in the pump.Make sure that it's going to WOT(linkage)
Then check the reeds.
If it's choking itself the rubber boot might not be fitting right.If your running 25/1 you should be able to see where the smoke is comming from.
It's possible the stator isin't charging.Do the test on that.J

 

[PaulO]

Re: First run 120hp Force issues

It is a 1991 model.

I haven't done the compression test yet but the motor now has 2 hours on it after 3x hone and 1 x oversize piston. New rings all round. 25:1 is to bed them in. I feel it is achieving the RPM range and the linkages are fully opening. It is doing 42MPH or 68Kmh so i guess I can't expect anymore than that.

The charging system has got me. I replaced the old Rec/Reg because the AC x2 were showing no difference in reading with reverse testing on the meter. the new rec/reg shows some difference. There is a small amount of charge indicated by needle movement on boat volt meter. I really need to charge battery fully and run and test again down at the terminal with the multi meter.

I am thinking I might have to stuff something down the leg to keep exhaust gas from choking the engine with the cowl on???

The tachometer is brand new (faria chesapeake Black SS)

 

[pnwboat]

Re: First run 120hp Force issues

You can check the output of the stator by measuring the A.C. voltage from the stator to the regulator. You should be reading about 15 - 16 volts A.C. on the two yellow wires coming from the stator to the regulator with the engine running. You can also check the resistance of the stator windings on the two yellow wires. It should read very low ohms...around .6 ohms.

There should be no exhaust leaking from the exhaust bellows. The exhaust bellows may have a hole, or it may not be seated correctly between the lower drive shaft housing and rear cover. There should be a spring inside the boot to keep it in place and sealed to insure the exhaust/water exit the motor through the idle exhaust holes.

 

[PaulO]

Re: First run 120hp Force issues

I checked the stator a month ago and from memory it was putting out 16 volts AC and the Ohms was 0.7.

I will check it again though for peace of mind.

The rubber boot for water exhaust seemed serviceable. I will keep my eye on that one.

 

[pnwboat]

Re: First run 120hp Force issues

Double check the output of the rec/reg right at the spot that it is connected to the wiring harness with the motor running. If you see the proper voltage there, then I would suspect a problem in the wiring. Corroded connections, blown fuse, etc. Check the positive wire that comes from the motor to the fuse box for your 12 volts.

 

[PaulO]

Re: First run 120hp Force issues

Second run today.

I am satisfied with the charge system and the rec/reg is working properly now. The one from the sticky - Universal Reg

The Tach does not register properly but the throttle valves are fully open at WOT

• 
  I have run an earth and a signal wire directly from the Tachometer to the terminal block at the engine. The only difference to last setup is I can get upto 3000RPM some times otherwise it sits around 2200RPM at WOT.

• 
  The next trick is to swap Alternator pickup wires at the regulator.

Pain in the A@#$ Issue: The engine will die at idle when the cover is on the engine. I have just gone back to 50:1 mix now the engine is run in but the same problem persists. There was water accumulating around the leg (inside the back leg cover and there is smoke getting in.) Could it be the rubber seal that runs around the lower leg and seals between the back cover? It was starting to split longitudinally in one corner.

Is it normal to have water inside between the back cover and leg?

 

[roscoe]

Re: First run 120hp Force issues

Yes, seal to the motor leg will leak exhaust to the intake, causing stall.

Speed is good, sounds like the tach or rectifier is the culprit.

80*f is too cool.
Temp should be closer to 140. Too hot to keep your hand on it for 5 seconds.
Check the thermostat, betting someone removed it, or it is stuck.

 

[PaulO]

Re: First run 120hp Force issues

Speed down 1-2 mph today due to a little bit of chop.

The rectifier/regulator is brand new and today was it's second outing. I have soldered the tach wire to one of the Yellow AC wires.

Two points:

• I was told to try the other AC wire for tach pickup

• There may be noise generated in the electricals and to put a capacitor (unknown value?) between the sync post and sync line for tacho

Also noted: When I trim down to the stop and continue holding the trim down button at WOT the RPM shot up 6-800 RPM. When the trim down button was released the RPM decreased by the same amount.

Any other suggestions?

The temp is CHT and the impellor is working (brand new). There is a power of water streaming from the Tell tale and It feels a lot cooler when hand is placed on Thermostat cover and cyl head cover than it did when it was on the muffs. It is about 80? F on the guage but I guess I could recheck it.

So are the seals still available and I guess it means the gearcase has to come off to get it on????

 

[pnwboat]

Re: First run 120hp Force issues

Sounds like there may be something wrong with the tach. It sounds like you've tried each of the A.C. terminals on the rectifier with same results? If so, many of the tachs have a selector switch on the back of them to select the number of poles to match it up to the stator. Could it be that yours is not on the correct setting?

Like Roscoe stated, the low temperature may be caused by the thermostat that is stuck open (or missing). I had the exact same thing happen to me on my first outing this year. There was a piece of debris that was caught in the opening of the thermostat preventing it from closing all the way. It was only open just a hair. Had to drop the thermostat in a pan of boiling water to get it to open up far enough to remove the crud.

As far as the exhaust leak...are you referring to the seal #17 in the diagram below?

http://www.boats.net/parts/search/Merc2/Force/120%20H.P.%20%281990-1994%29/0E000001%20THRU%200E093699/DRIVESHAFT%20HOUSING/parts.html

Typically there is a bead of silicone sealant between the powerhead and the top of the lower housing #1 that will prevent any exhaust leaking into the cowling area. To replace the seal #17, you have to take the powerhead off.

I would take a close look at the exhaust bellows #27 too just to be sure. It's much easier to change. Just have to remove the rear cover.

 

[foodfisher]

Re: First run 120hp Force issues

Doesn't #30 also stop exhaust from entering the lower leg?

 

[pnwboat]

Re: First run 120hp Force issues

#30 does seal off the lower portion of the rear and front cover of the drive shaft housing. While most of the exhaust should exit out of the lower exhaust snout and the idle relief bellows (#27), I suppose there may be some exhaust present around seal #30. Definitely worth taking a look at. Good observation.

 

[PaulO]

Re: First run 120hp Force issues

Thermostat is brand new. Boiled it up before install. Done 2.5 hours in river environment. Water feels reasonably hot at the pee hole.

I am yet to try the 2nd AC wire for tach pickup. Pole setting was moved off and back to 5 for 12 pole Stator.

I am thinking Part #30. Water sitting just above and smoke appeared to be coming from low but hard to see exactly where. Part #17 was a bit iffy but the rubber was still in one piece. The hole in the leg (metal mating surfaces) didn't seem to match as good as it should with the exhaust shroud. The block was sealed to leg with RTV sealant a few months ago. I don't believe this is the problem.

Is there an easy fix to part #30? maybe just take the back cover off and squirt some rubber compound around????

 

[pnwboat]

Re: First run 120hp Force issues

Make sure the thermostat components are installed in the correct order. I wouldn't rule out something getting stuck in the thermostat holding it open. I might be a bit paranoid since I just experienced this on my first outing this year. Anyways, this is not a show stopper. The exhaust leak killing the motor probably needs to be addressed first.

http://www.crowleymarine.com/mercury-outboard/parts/1470_180.cfm

Yes I would try some rubber sealant around #30. I don't think you have much choice since it's no longer available.

 

[foodfisher]

Re: First run 120hp Force issues

My part 30 had started to disentegrate due to fuel seeping down to it. When I discovered it's NLA, I cleaned as best as possible and used silicone to fill voids and seat it to the leg. So far so good. If it's beyond saving there has got to be an adaptable substitute. A little resourcefulness will prevail. Am thinking a hose of the right diameter, filled with caulk, for starters.

 

[PaulO]

Re: First run 120hp Force issues

Ok thanks. I will try something. It will be a while before I get back to the water so i can report here. STDBY

 

[PaulO]

Re: First run 120hp Force issues

I took the boat out for a run today. After placing RTV sealant around part 30 I must not have put enough. It still gets smokes in the engine bay when stationary and eventually cuts out. I guess I can live with it for the time being. Otherwise the engine runs great

I get 5200RPM @ WOT with a 19P prop. (Solas)