Turbo Installation Question / Troubleshooting

[BuoyScout]

Hey all. I'm looking for reassurance that I'm capable of swapping out a turbo (that might be causing us problems).

I can't find step-by-steps for a turbo swap-out (110hp Yanmars), so I'm looking for any special instructions on how to. Hopefully it's a simple unbolt/unclamp, remove, replace, bolt/clamp on.

I have a spare, so I was going to drop in the new one and see if that was the issue. If so, I'd clean the used one for the backup (or take it in to get cleaned if that's a better idea?).

TO NOTE: I may or may not have to do this, but regardless it'd be great to know if I ever have to.
...

Here's what we're dealing with:
- Our SB engine can't get past 2500rpm (typical WOT was 3000-3200rpm)
- When docked, in neutral, and throttling to 3200rpm a few times, the exhaust is blowing out a concerning amount of oil after every 3rd or 4th sea trial
- I replaced the Racor and on-engine fuel filters

We travelled from FLA to Toronto last fall on the ICW and I suspect the low-speed cruising didn't agree with the turbos. I did make a habit of throttling to 3200rpm 5 times when docked - after a day of 10mph cruising.

This began at the very end of last season, and shortly after the port engine began to lose rpms as well - but - after replacing the on-engine fuel filters the port engine came back to 3000rpms. It hasn't helped the SB engine at all.


Any help / advice would be greatly appreciated!

[Nick]

Removing and reinstalling is fairly straightforward although there’s a lot of grunting and cursing required as you snake your hands around to reach bolts that seem impossibly tough to put a wrench on. You most likely will end up removing some other parts to facilitate access. If you remove and clean the turbo you might as well remove and clean air filter at same time.

Your issue is tightly correlated to mine in the “black exhaust smoke” post. Do your motors blow a lot of black exhaust, or just the oily substance you mention? If the latter, it may not be the turbo, particularly if you just replaced the turbo. In our case, we run our motors at 3,000 all the time and still had a turbo issue(s). Cleaned both turbos and that resolved most of the black smoke problem on one side, but we still can’t get more than 3,000rpm on the other. Winding to WOT in neutral does little more than prove the issue isn’t a problem with mechanical throttle linkage. In our case, I suspect there is some issue around the injectors (even though they’ve been recently serviced) and will post resolution when achieved(!).

[duetto]

fwiw, years ago we had our injectors serviced at a local diesel shop. we have 75s. when i re-installed and took out for test we could barely make 2600 vs our normal 3400. engines ran smoothly but just maxed out. removed and went back to the shop and went over what they did, incl installing some new pieces. turns out the used wrong size "jets" (my term) which didn't allow enough fuel to be injected. working with mack boring we got correct parts and problem was solved.

[BuoyScout]

Thanks guys.

Nick, no, we're not getting any black smoke, just the black oily mess. The turbo wasn't recently replaced, I just have a spare.

I'll see what I can learn about the injectors... just to be able to have a relatively educated conversation with a mechanic.

[BuoyScout]

UPDATE on our RPM issue:

Before tackling the turbo swap out, I tried a recommended SeaFoam "hot bath" fuel injector treatment process - that didn't help - maybe made it worse. After having done the hot bath I was now getting black smoke at 2200rpms.

So, swapping out the turbo it is. And it looks like that's what it was (or at least one of the culprits). The old turbo had seized up - choked with a ton of carbon build up. I've removed and replaced it, and taking us out for a test run tomorrow hopefully.

Sea trial results to follow...

The turbo swap out was just as described - thanks Nick. Cleaned the air filter while I was at it, and didn't have to remove anything else. I'd add a reminder to anyone trying it to remove the upper coolant hose connection first (seems so obvious now). Also, if a failing turbo is on your list of suspects, you can quickly check it by removing the air filter and sticking your finger in the turbo to see if the turbine is moving freely. Not a full diagnostics obviously, but I would have known quickly that it was seized.

Ballpark: 6hrs (2hrs max next time)

[Nick]

If you’re in there cleaning the turbo, you might as well take the exhaust cooler off (next level gyration!) and clean it up too. These engines are sensitive to any exhaust restrictions whatsoever and once you have a turbo issue you might as well go through the whole system. We have taken ours off and it’s dirty too.

[BuoyScout]

Sea trial SUCCESS! We're back up to 3200rpm. No more black smoke or oily exhaust discharge. I didn't get your last msg until after reassembly Nick - I'll get back in there and clean the exhaust cooler too.

Thanks again for all the comments and help.