YAM STERNDRIVES

[nickyg]

HI ALL My first post
Have had my new shetland 27 formerly called atlanta 27 since march this year.Having sorted out the teething problems i am getting on ok now. Is it normal to have these problems on a new boat ? apparently i am told you are unless paying £100,000 plus
Anyway i have a yam me370 165 hp sterndrive which seems a great engine but it has started to smoke on tickover other than that its spot on ( touch wood). i have had a yam dealer out and he says its bore glazing. Could this be true after only 60 hours?. The boat is based on the river trent so admitedly i have a little way to go before i can go above 8 knots
so i spend say 70% going slowish & 30 % going fastish sorry to ramble on look forward to any replies Has anyone had experience of the atlanta 27 at sea
nicky g

 

[longjohnsilver]

It's a big engine to use at slow speeds so glazing could well be the problem. Diesels like to be worked hard which is difficult on the river but if you want to keep the engine healthy you'll have to find a way of regularly opening her up under load for a reasonable run.

Sorry, don't know anything about your boat, no doubt someone else on the forum can help. Is it a brand new boat or new to you?

 

[nickyg]

yes its abrand new boat .Do you think a coarser oil might help .
Thanks for the reply You see lots of large boat on the river so all i can assume that lot of people have this problem
nicky g

 

[longjohnsilver]

Nicky I'm no mechanic so don't really know about different oil although I would think that you should stick to recommended grade. Also don't see how it could make any difference to glazing of the bores.

Yes it is probably a problem for lots of boats although many of them will have much smaller engines and lots of them will hardly be used at all! I suggest that you speak to an engineer for further help.

 

[BarryD]

Welcome to the board. No experience of your boat or engine, but how many hours do you think are on the engine?

 

[Guest]

I have worked on the larger 240 hp engines and outdrives, I am local to the river trent, Newark area and an engineer.

I presume you are to go to sea via the Trent/ Humber, have not seen your type of boat at sea, thought it might be a bit flat bottomed for sea work.
It can get very rough on the Humber in east/ west winds above about f 3/4 against the tide, as for the smoke it will smoke at low revs, as it is not properly warmed up.

neilc has 2 yamahas in a Draco at Newark which I have worked on, perhaps a private message to him will pull out some answers.

Paul.

 

[Guest]

Re: new boats, bores

There can be just as many problems on biggger £100K plus boats, but the problems are of a higher quality, so you get even more mad about them.

It will smoke a bit more when it's a bit older. If it's bore glazing, there are additives that you get get (?dunno wot they tho) that can help reduce the glaze, they say.

Maybe run the engine at standstill in neutral for half an hour to warm it up fully? Bit of smoke is not a megaproblem.

 

[nickyg]

thanks for the reply & the boat is new with only 70 hrs on from new

 

[adarcy]

Re: new boats, bores

Dear Matts and nickyg

Smoke from low revs in a used engine is one thing but due to bore glaze on a new one is not a miniproblem.

Bore glazing is due to not enough load rather than not enough revs. The turbos don't spin up pressure, the bmep is low, the rings rattle around and some combustion products leak past which the rings polish. Therefore, there is a poor seal between ring and bore wall and it all continues. The avoidance/treatment is to put the engine on load which presses the rings etc etc.
Glaze is a problem of new engines as one that has been run in moderately well or properly will have good ring seating.
Matts, you may be right that there is some deglazers around but the VERY WORST thing to do is to run an engine to warm at idle. That is guaranteed to worsen the glaze. Obviously, one is always told not to load a car engine much until it is warm but they don't semm so prone to glaze ? because there is direct gearing load rather than slip via the propellor. On our boat, the engines never get above 60 C until we get out of the river and onto the plane, the heat soak is too much.
My advice, for what it is worth, is to move off as soon as the engines are warm enough to idle or run when put into gear to get some sort of load on them while warming up.
Equally obviously, IMHO, is that glaze is a much bigger problem in fast boats with v powerful engines because they have virtually no load at harbour/river speeds - high tickover speed/efficient hull etc

Flame away

Anthony

 

[Guest]

Re: new boats, bores, load

ooh, no flaming from here.

I understood that bore glazing much less likley these days with new materials (?). Also, not sure what you can do do unglaze, other than short rebuild inc new rings and wet+dry on bores...hence tentatively advised "additives" Is 60 hrs is long enuf to have developed a real "glaze"?

So he needs a decent engine load? How's he do that then, I wonder? Perhaps find contrete pontoon or quayside, attach on all horiz cleats, slip into gear and sloosh some water thru? I've seen this done at quick tickover, not at high revs, so carefully does it else rip the cleats off? What do others do?

 

[jfm]

Re: new boats, bores, load

Agree would help to load it. This presses rings harder against cyl wall. Also agree not to warm up in idle before driving off. Drive off soon after startup so the engine gets hotter faster.

Re tying up to pontoon and running in gear, good idea if cleats strong. But for big outboards they used to sell special tank test "props" that load the engine but do not create fwd motion. Just sloosh loads of water around I suppose. Can you get these for outdrives I wonder? Or if it is a duo prop twin installation then swap over ONE prop from each leg, then you will have forward and backward thrust at the same time from each leg, and lots of spray I suppose. Is that a really daft idea?

 

[Guest]

Re: in reverse?

um, lot of fiddling to swap props. And do they go on properly the wrong way round?

Would it be better to do this in reverse gear, from anchor and fwd cleats?

 

[adarcy]

Re: new boats, bores, load

jfm and matts

I'm not at all happy about this tying on and revving up. You/he had better have some v strong bollards/piles/whatever to tie onto if you want to load the engines up. The originator to all of this "nickyg" has a 165hp motor and I'd guess that one would need 1/3 throttle or so to load the engine/turbo - certainly enough power to do more than 10 knots. So about 50 hp via weedy small boat cleats and something pretty solid to tie onto imNotSoho.

As regards twin sterndrives ahead and astern, gives a mighty twist if you go above idle as we forund out when we tried it on our Princess45 (that's how they turn innit?). Our previous boat was a twin Volvo Duoprop and to the best of my memory the props are not handed at all. The front bigger one goes one way and the aft smaller (? steeper-pitched) goes the other way driven by the concentric shaft. That way there is only one set of 2 props for each engine and prop setting not 4 and a single will track true and there is no paddlewheel effect. Simple eh?
I am afraid you can swap props side to side as much as you like.......

Anthony

<P ID="edit"><FONT SIZE=-1>Edited by adarcy on Mon Dec 17 16:11:46 2001 (server time).</FONT></P>

 

[jfm]

Re: new boats, bores, load

adarcy thanks for confirming, yes it was a daft idea. Best answer is to find some open water soon and give it a massive blast to deglaze. Till then not worry about glaze, cant be much after only 60hours or whatever