Mercury 1500 105Hp

[novice boater54]

Hi, need to know the characteristics of this particular motor as I'm working on it for a friend. First what is considered good compression or at least minimum.
How are the electrics such as ignition (thunderbolt) utilzed?
Ignition key missing and unavailable on a mercontrol. Will one have to replace whole switch or can a key be made from a locksmith with appropriate key blank?
How does trim or hydraulic lift work as the motor at least operates but no lift action?
There is a knob and a sticker that indicates engage or lock and disengage?
Don't know how this works and does one have to bleed air from system if oil level low?
What is adequate oil/fuel ratio?
Finally is this a good motor?
Thanks

 

[achris]

Re: Mercury 1500 105Hp

Hi, need to know the characteristics of this particular motor as I'm working on it for a friend. First what is considered good compression or at least minimum.

Compressions should be within 10psi of each other. Good compression would be around 110psi (depending on the gauge).

How are the electrics such as ignition (thunderbolt) utilzed?

Depends on the year of the engine. Does it have a distributor or 2 switchboxes?

Ignition key missing and unavailable on a mercontrol.

Horse hockey!!!! Open the control box and read the number on the keyswitch housing. I will be a 3 digit number between 100 and 150. Go to any Merc dealer with that number and he'll be able to get a key for you...

Will one have to replace whole switch or can a key be made from a locksmith with appropriate key blank?
How does trim or hydraulic lift work as the motor at least operates but no lift action?

Check the fluid level

There is a knob and a sticker that indicates engage or lock and disengage?
Don't know how this works and does one have to bleed air from system if oil level low?
What is adequate oil/fuel ratio?

50:1, use a good quality TC-W3 rated oil.

Finally is this a good motor?
Thanks

Yes, I love them... Getting a bit old now, but still the best power to weight ratio ever made.

Chris........

 

[Chris1956]

Re: Mercury 1500 105Hp

In addiiton to what Achris said,

The last Merc 1500 (150HP/300 pounds) was made in 1977 and has a distributor ignition. Use 5W-30 motor oil in the PTT unit. Turn the knurled knob CCW to engage Power Trim. The trim cylindres need to be individually bled. A Merc service Manual is best.

 

[novice boater54]

Re: Mercury 1500 105Hp

Hi should have changed something this is a 150Hp motor.
I was able to get the number from the key cylinder and get two keys from dealer.
Compression isn't good, #1 reads 0,#2 reads over 120, #3 reads 30lbs, #'s 4 & 5 are ovr 100-115 as well and #6 I wasn't able to get a reading at present without removing lower shroud but it seems strong with finger over hole. Could this be rings and how big a job is this to redo this with a good manual?
This motor has been sitting for a year or so so...?
Fuel is getting to carbs (dripping out from ack of venturi) but not to cylinder possily I'll have to remove carbs and inspect and clean, is this an easy job without getting carbs out of sync by keeping connection rod intact for simplicity without proper sync tools?
I had a leak at the fuel pump but replaced gaskets and diaphragm.
I'll have to inspect the filler hole as I did see a small screw in upper right corner of trim motor assembly. How does one bleed system? Motor doesn't fall to full extension or compressio of cylinders but leaves about 2-3 inches of cylinder exposed at the bottom and then doesn't appear to sit level?
I did notice a bottle of hydraulic jack fluid on the boat would tuis be suitable as it has a flip up squirt nozzle and I'm suspecting this and whatever is inside was used previously. How would one drain and reinstall either 5W30 oil or ATF fluid?
Thanks for all the kind and pertinant replies it helps and one last question is a seloc manual a good on or is there another better DIY manual which might be better understood for the DIY?
thanks

 

[achris]

Re: Mercury 1500 105Hp

Hi should have changed something this is a 150Hp motor.
I was able to get the number from the key cylinder and get two keys from dealer.

That's good news...

Compression isn't good, #1 reads 0,#2 reads over 120, #3 reads 30lbs, #'s 4 & 5 are ovr 100-115 as well and #6 I wasn't able to get a reading at present without removing lower shroud but it seems strong with finger over hole. Could this be rings and how big a job is this to redo this with a good manual?

This is not good news... and it sounds worst than rings. 0 compression usually means a detonated piston.

This motor has been sitting for a year or so so...?
Fuel is getting to carbs (dripping out from ack of venturi) but not to cylinder possily I'll have to remove carbs and inspect and clean, is this an easy job without getting carbs out of sync by keeping connection rod intact for simplicity without proper sync tools?

You'll be setting up the sync after you rebulid the powerhead.

I had a leak at the fuel pump but replaced gaskets and diaphragm. I'll have to inspect the filler hole as I did see a small screw in upper right corner of trim motor assembly. How does one bleed system? Motor doesn't fall to full extension or compressio of cylinders but leaves about 2-3 inches of cylinder exposed at the bottom and then doesn't appear to sit level?
I did notice a bottle of hydraulic jack fluid on the boat would tuis be suitable as it has a flip up squirt nozzle and I'm suspecting this and whatever is inside was used previously. How would one drain and reinstall either 5W30 oil or ATF fluid?
Thanks for all the kind and pertinant replies it helps and one last question is a seloc manual a good on or is there another better DIY manual which might be better understood for the DIY?
thanks

Runaway from any manual except OEM... Regardless of DIY or professional... Especially for a powerhead rebulid, which is where you're heading...

Chris......

 

[achris]

Re: Mercury 1500 105Hp

..The last Merc 1500 (150HP/300 pounds) was made in 1977 and has a distributor ignition.....

Thanks Chris,

I couldn't remember if the in-line 150s got a ADi at the end (couldn't be bother looking in yet another manual more like. )

Cheers,

Chris.......

 

[achris]

Re: Mercury 1500 105Hp

novice boater54,

Here's layout of the ignition system....

 

[ClassyGlassy]

Re: Mercury 1500 105Hp

This is the motor that I have and I'll tell you first to NOT waste your money on a Seloc manual, go with a GENUINE Mercury manual from here:

http://www.marinepartsman.com/

He's a great guy to talk to on the phone and will get it right out to you. I spoke to him earlier today for some parts and he still has more of the Mercury Maintenance manuals in stock!

Carbs are simple, don't worry about synchronization. Purchase GENUINE Quicksilver rebuild kits and install according to the manual.

Get NEW plugs!! I like to use the L76V plugs that are OEM.

I think there is a process to checking compression.......if you don't ground the plug wires during the check, the coil will overstrain itself trying to jump to the plug causing coil failure and possibly other ignition system failure!

Low compression reading means scored cylinder wall, bad rings, or failed/burned piston. If it has sat for a long time it could be rings. Sometimes pouring straight TCW3 into the cylinders and letting them sit for a day then turning it over for several revs will cause the rings to stand up and say hi. If this doesn't work, you're into a tear-down phase. The Mercury Manual will tell you everything you need to do. The "Marine Parts Man" can get you all the parts you need.

This is a wonderful motor and the phrase, "they don't build them like they used to" is prevalent here!

 

[ClassyGlassy]

Re: Mercury 1500 105Hp

achris beat me to the punch again!

I will add this about the T/T........

I was told by the dealer to use a Nondetergent SAE30 oil to fill it with and the OEM Manual will tell you the procedure for that as well.

 

[novice boater54]

Re: Mercury 1500 105Hp

Could you elaborate on what TCW3 is and is it ok left in the motor or is it expelled when turning motor over after sitting with plugs removed?
Regarding carb sync if one left the connecting rods attached could it be done that way?
Currently I don't have any manual for this beast.
I'm hoping for a better result.
Removing the water jacket cover is this the cover on the side of the motor or the cover where the plugs are in order to view and diagnose the situation?

 

[achris]

Re: Mercury 1500 105Hp

Could you elaborate on what TCW3 is

Two Cycle - Water cooled, standard #3. It's the oil that you mix with the petrol for these outboards.. (50:1)

and is it ok left in the motor or is it expelled when turning motor over after sitting with plugs removed?

It's expelled.

Regarding carb sync if one left the connecting rods attached could it be done that way?

Definitely NOT!

Currently I don't have any manual for this beast.

Before you do ANYTHING else, get one...

I'm hoping for a better result.

A better result than what?

Removing the water jacket cover is this the cover on the side of the motor or the cover where the plugs are in order to view and diagnose the situation?

Water jacket cover is the cover over the cylinder head area. All you'll view in there is the cooling water gallery. The cylinder head is integral with the block and cannot be removed. To get a half look at the pistons, you need to pull the powerhead off the drive shaft housing and remove the exhaust covers.... But get the manual FIRST!

Chris............

 

[Chris1956]

Re: Mercury 1500 105Hp

You can pull the transfer covers off the starboard side of the motor, with the powerhead still installed on the midsection. Remove the spark plugs and shine a flashlight into the plug holes, while looking into the cylinders. You will see scratches on the cylinder and piston on #1 cylinder.

BTW - the exhaust ports will likely show more accurate damage, however, you should pull the powerhead to get to all the bolts on the exhaust cover (port side of motor).

 

[achris]

Re: Mercury 1500 105Hp

+1... I rarely do that though. If the compression is that low, the power head's got to come off anyway, and I 'll get a look at the pistons soon enough.

 

[novice boater54]

Re: Mercury 1500 105Hp

Hi thanks I'll defintely get the manual before doing any major tearing down just gathering information at present. Can one remove power head with remaining portion of motor still attached to boat and is it difficult. I see four main bolts which appear to attach power head to lower unit (or the lower shround not sure though and ofcourse wahtever attaches the crankshaft to the lower uint drive shaft itself.
Another few questions does all the exterior paraphanalia have to be removed when doing pistons etc, such as the coil wires switch box etc?
Basically how much does the rings and pistons cost and what will have to be done (either hone or bore job) on cylinders to do a basic complete job?
Is there a kit for the related gaskets as well as once the motor is split in two is there a type of sealer required to resael the two halves?
I just sort of need an overview of waht needs to be taken apart and looked at until I can obtain a manual.

 

[achris]

Re: Mercury 1500 105Hp

Hi thanks I'll defintely get the manual before doing any major tearing down just gathering information at present. Can one remove power head with remaining portion of motor still attached to boat and is it difficult. I see four main bolts which appear to attach power head to lower unit (or the lower shround not sure though

Power head can be removed with the rest of the engine attached to the boat... It's easier that way anyway. Not 4 bolts, 8 nuts on studs. The rest are behind the a small cover.

and ofcourse wahtever attaches the crankshaft to the lower uint drive shaft itself.

Splined shaft, just lift the powerhead up and it comes off.

Another few questions does all the exterior paraphanalia have to be removed when doing pistons etc, such as the coil wires switch box etc?

Yes. The piston and crankshaft assembly is the first thing put in the block...

Basically how much does the rings and pistons cost and what will have to be done (either hone or bore job) on cylinders to do a basic complete job?

Depends on how much work needs doing. And you only replace the pistons that need doing. Not like a car engine where if one needs replacing, then all have to be done. Check on the Wiseco website for pistons. They come in standard, 20, 30, 40 thou oversize and cost $120 each, that includes rings. Or if you're confident enough to wade through the different piston types, HERE at iBoats.

Is there a kit for the related gaskets as well as once the motor is split in two

Gasket sets are available from iBoats. Click HERE to have a look at it.

is there a type of sealer required to resael the two halves?

Just some Loctite Master gasket sealer, #518. Also some high temperature epoxy for the water jacket cover bolts, inside the exhaust chamber.

I just sort of need an overview of what needs to be taken apart and looked at until I can obtain a manual.

You need to take apart everything for this job... And if you're going that far, do it right... .

Chris......

 

[Chris1956]

Re: Mercury 1500 105Hp

Before removing the powerhead, drop the gearcase, and disconnect the electrical connection to the battery. You will need some kind of light duty hoist to pull the powerhead. I usually use a POS block and tackle. I bolt the B&T end to two of the flywheel bolts.

 

[ClassyGlassy]

Re: Mercury 1500 105Hp

Just so you have the information....according to my '77 Operation and Maintenance Manual for Merc 1500, 1400, 1150, and 900 the 1500 was rated from the Manufacturer to have 155hp

I haven't heard any differences in the powerhead from earlier models so I'm sure my '76 is the same as well as the later models, '78-'82.

 

[Chris1956]

Re: Mercury 1500 105Hp

1977 was the last year for the Merc 1500 Inline six Model. The 1978 Model was called a 1400, but was nearly identical to the 1500. There may have been a 1979 Merc 1400, as well, but I think that was really the last year for that flavor of inline six.

 

[ClassyGlassy]

Re: Mercury 1500 105Hp

Thanks Chris,

this is one of the reasons I love this site. I get to learn something new everyday!

 

[ClassyGlassy]

Re: Mercury 1500 105Hp

Clarify one more thing for me........Mercury rated these earlier motors at the powerhead not the prop, correct?

So my 155hp rating is Powerhead HP?

Is there a way for us to find out the Prop HP?