03 F40 Fourstroke issues

[rivman05]

Good afternoon,
I purchased an 03 F40 fourstroke and it spun the rod bearing on cylinder 2. I have been told by our local shop that they have been told by Yamaha that they don't recommend rebuilding short blocks but to buy a a fresh short block. Anyone here have any experience with having a short block rebuilt and have it survive more than 10 miles? I didn't get more than 3 miles on this outboard before it seized, and waiting on my Suzuki to get out of the shop. Thanks for any insight.

[boscoe99]

Yamaha does not have a position not to rebuild a block. In fact, they go so far as to put information within their service manual as how to go about doing it.

Now what Yamaha does do is to recommend that an out of specification crank shaft be replaced rather than be repaired. But there are plenty of machine shops that can rebuild a crank shaft journal and then grind it back within specifications.

Two shops come to mind that you should give a call. Jasper Engines and Chris Carson Marine. See what they have to say.

Marine Products | Jasper Engines & Transmissions

A South Florida marine service and supply shop specializing in reed valves and the rebuilding and re-manufacturing of outboard motor powerheads and lower units - Chris Carson Marine Service and Supply.

By the way, most Yamaha dealers these days seem to be parts changers. Old for new. They are not equipped to be engine rebuilders. So of course they will recommend that new stuff be purchased as opposed to repairing old stuff. They have less risk and make more profit in doing so.

[panasonic]

As the others said a good rebuild shop should be able to make that engine work as good as new. It is all about how much money you are willing to pay.

[rivman05]

I know, I used to rebuild big block fords, chevys, buicks, pontiacs before I was a Ford technician. Dont have a shop to build it in tho but have all the tools. The motor sat for 3 years not touched. The rest of the bearings were fine, one thing that i cant find in the service manual is an oil gallery flow diagram. Wondering if cyl 2 gets oil last?

[panasonic]

Take the crank in and have that journal reground and put oversize bearings in, if available. If the other two journals are OK then back together and go.....

Make sure oil passages in crank are open...and clean.

[rivman05]

Yes it got cooked. All of the other beairngs were fine, just an issue with cyl 2. Nothings floating around, our diesel shop where i work has flushed the thing out with a highpressure adapter we made for flushing passages out where the oil filter goes. I have a line on a couple of donor power heads that still rotate, so im thinking of buying one and order new rod bearings and throw it together. Thanks for the diagram, it kinda answers some questions. Bores were full of oil so the pistons and everything else is fine and well oiled. Still has oil film on the other rods and all crank bearings

[rivman05]

Don't ask why you can't post "G0lden"

Couldnt figure that one out, made me laugh tho

[rivman05]

Can anyone enlighten me as to what I need to do to get this picture broken down the way it shows in this link? I bought a parts motor for 100, and it has most everything I need, but the crank on cyl 2 is toast.

I see the plate comes up, then the oil pickup tube and oil pan should be able to be transferred to my previous F40.

2003 F40MLHB Yamaha Outboard OIL PAN Diagram and Parts

From what I guess is that I have to tap the upper most plate off? Then the rest I can deal with from there.

[rodbolt17]

I have probably rebuilt more engines than any two posters here.
\
that being said Yamaha does NOT offer any undersized bearings.

that means having the crank welded ground and heat treated.
by that time your cost for machine work exceeds what the part costs.

and yes I have actually welded and ground crank shafts.
yes I have nitrided them.
yes I ran the heat treat ovens at GOEX.

used to have a saying.
speed cost money.
how fast you wanna go?

[boscoe99]

While it is true that Yamaha does not offer bearings for an undersized crank shaft journal, Yamaha does offer bearings that come in different thickness's.

You could have your crank shaft cleaned up as needed for maybe not a lot of money and then see if any of the existing Yamaha bearings (two of the thickest ones) can be used to get your clearances within allowable limits.

Of course there are a number of options such as finding a used serviceable crank shaft, buying a new crank shaft, buying a new short block, etc., etc.

I suspect that if you called Jasper engines they may have a source for bearings that are even thicker than those offered by Yamaha. Where there is a will there is a way. And Jasper has the will to rebuild engines.

Many are doing what Yamaha did not intend to be done. I think the Japs have a completely different mindset when it comes to repairs than what 'mericans have.

Good luck and keep us posted. We (most of us here) like folks that get out there to try and get stuff done.

[rivman05]

I figured out how to get the oil pan, pickup tube etc out. I didnt ask about undersized, Im looking for oversized, as turning the crank down 10 or 15 thousanddths and have bigger bearing to fill the gap. What is the difference in thicknesses in the different colored bearings? I cant find it listed anywhere. Im assuming one is standard, 10 and 20 thou over but Im not going to buy bearings until I can get actual measurements. I have considered buying a crank outright but damn are they spendy. Can get complete long block v8s for the same price...

[boscoe99]

I figured out how to get the oil pan, pickup tube etc out. I didnt ask about undersized, Im looking for oversized, as turning the crank down 10 or 15 thousanddths and have bigger bearing to fill the gap. What is the difference in thicknesses in the different colored bearings? I cant find it listed anywhere. Im assuming one is standard, 10 and 20 thou over but Im not going to buy bearings until I can get actual measurements. I have considered buying a crank outright but damn are they spendy. Can get complete long block v8s for the same price...

Yes, an oversized bearing for an undersized crank shaft.

The thickness of the Yamaha bearings is not known to me. They are metric and not SAE size. Would be in decimals of millimeters. But Yamaha uses colours, not numeric values.

How much to have the crank shaft cleaned up? If not a lot of money it might be worth a gamble. After clean up, see if it is within Yamaha specification. If so, you are good to go. If not, 'spearment as they say in NASCAR. Gamble again by buying two of the thickest bearings that Yamaha offers. Install them in the block. Insert the crank shaft with plastigage being used to determine if the clearance is within limit or not. If within limit you are good to go. If out of limit you get another decision as to what to do.

Where is Mr. Almetelo?

[rodbolt17]

the range in the thickness is less than .003"\

not really enough to cover a good polish job.

you select bearing by the numbers on the crank and the numbers on the block and a chart.
then you plastigage it and make any final adjustments.
usually it is correct from the chart.

it can be a pain in the rear.

once the mains are plastigaged(use the original crankcase bolts) then clean the gage and reinstall with new bolts.
same for each rod assy.