View Full Version : Update on the MERC Saga...

26-09-2008, 11:20 PM
Hi All

For those that don't recall reading the saga:


Well, they replaced the Spark Plugs with a 'non-resistant' plug and guess what, didn't take long for another meltdown! This time i was caught out in the middle of the night in the Bay with a motor that wouldn't run! It did eventually but a midnight curfew turned into a 3am very p#ssed off saga!

Needless to say, 1st thing in the morning i dropped it off to xxxx Marine and made my demands very clear:

Replace with brand new motor (least preferred)
Upgrade to a 4 stroke and i'll pay the difference
Refund my money

One thing for certain was that the boat wasn't leaving the yard with that motor on it! Anyway, got a call today saying that they were happy to upgrade for the difference, to which i agreed. The options are either a:

Merc 40hp 4-stroke, or
Merc 50hp 2-stroke.

There are +'s & -'s for both and while i like the idea of more power, i also like the idea of a 4 stroke for obvious reasons! The main issue with the 4-stroke though is that is circa 50kg heavier than my current motor as opposed to the 50 2-st which is circa 25kg heavier. I am putting it on a 4.5m CC Savage (approx 20yrs old).

In addition to the weight issue, it will mean a slight reduction in the Max speed (currently circa 45k's/hr).

Please feel free to provide an opinion and also if anyone has experienced any problems with either motor, would love to hear about it!

Take Care T

26-09-2008, 11:31 PM
That really Sucks that the Issue was not fixed. 50KG is not that much. You cannot go wrong with a DI or 4 Stroke Donk.

27-09-2008, 08:42 AM
Ooooo... 50kg, thats 2 plastic fuel tanks full of fuel, but its slightly worse as its hanging on the back of the boat... How does the boat handle with its current engine? Feel at all heavy in the rear end? Whats your gut feel with another 50kg on the rear?

If you can, it would be good to take the boat back to the water one last time and launch it (don't need to run the engine) and add the extra 50kg on the back of the boat. Teenage kid squatting on the engine, wife if shes 50kg etc etc and then you will know EXACTLY how the boat will sit with the extra 50kg.

I think another 50kg on the rear of a 15 footer is going to spell trouble.


27-09-2008, 09:20 AM
your boat is twenty years old and warranty is not a issue why not weld two step ups on the back but build a flotation box under them. than go the four stroke should be sweet.

27-09-2008, 10:13 AM
mate have a 50 hp 4 s merc on a 470 quinny coast runner - latest model efi and touch wood no probs with it to date - and appears to be a good motor so far - i would go 40 hp 4s or even the 50 hp 4s if at all poss
see you rob

27-09-2008, 10:19 PM
Thanks fella's! The weight is probably the only thing playing on my mind i guess with the 4st!

I guess i haven't noticed too much difference when i've run 2 full tanks as opposed to part of 1 and had another person at the back as opposed to not! I guess it's only an issue if i have 2 full tanks & another person at the back all at the same time, which isn't too often... But yes, 50kg is a fair bit extra hanging off the back. hmmmm, might have to look at extra bracing/support etc...

Take Care T

28-09-2008, 06:38 AM
if the 50hp is an opti than I would go that way. better weight, same fuel etc

28-09-2008, 07:46 AM
if the 50hp is an opti than I would go that way. better weight, same fuel etc

They do not make a 50HP Optimax.

28-09-2008, 08:28 AM
looks like the answer is No I just figured that you can get a tldi 50hp and an etec 50hp than you could get an optimax guess I was wrong.

28-09-2008, 11:04 AM
T if I was going to go the 4 stroke option I would up the power to the 50 hp to make up for the added weight. I have seen your boat and don't think the added weight on the back will be too much of an issue. I know it is probably a dearer option again but probably worth it. If you have been used to the get up and go of the 40hp 2 stroke you may think the 40hp 4 stroke is a slug by comparison and possibly become a little disappointed. Shame that you had so much trouble with your motor. As you know I have the same motor and after some initial running in teething problems I now could not be happier. It never misses a beat and is running as sweet as a motor can. I recently put a Solas stainless prop on it because the original prop was wearing paint off in s strange spot on the blades. When I had it checked out I was told that it was not built too well and should not have made it past the quality controllers. It makes a good spare anyway.
Best of luck with your new motor. Hope it serves you better than the last one.



28-09-2008, 12:34 PM
They do not make a 50HP Optimax.
In that case get the 4st...

28-09-2008, 03:52 PM
Don't know the boat, but for the life of me I cannot see how the weight of a 40 4s can be an issue on the back of a 4.5 m boat.

29-09-2008, 01:44 AM
Don't know the boat, but for the life of me I cannot see how the weight of a 40 4s can be an issue on the back of a 4.5 m boat.

WIL, it's the fact that i'm not sure that an extra 50kg in 'dry' travel is ideal and whether the back will sit lower in the water. It's an old tub so doesn't have high back/sides... I'll discuss with the dealer in detail a bit more...

POO, not wanting to spend any more than i have to for the upgrade so it's one of those 2 options.

Thanks for comments fella's!


30-09-2008, 04:57 PM
T1, does it have to be a merc, is there no other option from the dealer where by you could consider a DI or another perhaps lighter 4 stroke?

30-09-2008, 05:36 PM
Where are your fuel tanks now?
Can you put them up the front?
I have a 60hp merc on the back of a 4.6 dory. It just fits on with both weight and hp ratings.
I had the tank (50lt) at the back and i have to tell ya allot of water come over the stern on fast ish decel even at half full.
To fix that i just put the tank up the front and now it sit quite level in the water and no water comes in.


30-09-2008, 10:27 PM
Thanks again Guys!

I spoke with someone who knows my boat well and he advised to go with the 50hp 2st - totally different build (ie US and not rebadged Tohatsu) and he was also of the opinion that my boat could do with the extra power...

So i have gone with that option!

Take Care T

30-09-2008, 10:42 PM
when you consider that the 30Hp on the back of my boat is about 70KG and the 40HP two cylinder weighs the same..... an extra 50KG is quite a lot.

When you consider on an aluminium boat the motor may weigh 1/2 to 2/3 the weight of the hull....... the weight of the motor is a significant issue.

particularly with those low sides and stern.