Sometimes turbo not winding up on my Mercruiser 1.7tdi. is it a wastegate problem?

[Steve10001]

Hi, new boatist here with a question for all you boatanists.
Basically, i can get my boat up to plane from cold with the turbo working fine, but if I throttle down to idle for a few seconds ( to change drivers for example) and then throttle up to try to plane the boat again, it wont rev more than 2000rpm, and the turbo wont kick in. It takes a minute or so of waiting on idle / stopping / starting the engine before it goes back to normal again. ( this doesn't happen all the time, but it's becoming more frequent)
Any ideas?


P.s im new here, plus im new to boateneering, so be gentle.

[beamishken]

Probably wastegate sticking open they are very troublesome on that engine, usually stick closed & run overboost & melt no 6 piston. Sounds like yours is sticking open after your first run & not closing again until it cools slightly

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[Steve10001]

Originally Posted by beamishken

Probably wastegate sticking open they are very troublesome on that engine, usually stick closed & run overboost & melt no 6 piston. Sounds like yours is sticking open after your first run & not closing again until it cools slightly

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Thanks bro, I'll get it looked at straight away!

[beamishken]

Originally Posted by Steve10001

Thanks bro, I'll get it looked at straight away!

Haha just noticed my typo, no6 piston, it should have said no4.
If you unbolt the wastegate actuator via the two bolts you can operate the wastegate back & fourth & squirt with wd40 or similar. Worthwhile checking its free now & then because if it sticks shut it becomes terminal & you dont know until the damage is done

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[HDAV]

These are based on the gm/fiat car/van motor iirc not sure if parts are interchangeable but from when I was looking you can buy running car with engine for the price of a wastegate from merc………

https://www.rib.net/forum/f36/cummin...nce-77948.html

[beamishken]

Originally Posted by HDAV

These are based on the gm/fiat car/van motor iirc not sure if parts are interchangeable but from when I was looking you can buy running car with engine for the price of a wastegate from merc………

https://www.rib.net/forum/f36/cummin...nce-77948.html

I've had a few of these in bits & yes they are the Isuzu built engine used in Astras etc. The block & head are the same, starter & iirc alternator from some vehicles fit. Gaskets & filters can be used from the cars. Crucially the pistons injection pump & injectors all differ so its not a straightforward swap. That said many folk have fitted automotive pistons & they do run, how long for is anyones guess. The life expectancy of those engines in a sports boat or rib isnt good so maybe cheap rebuilds are the way to go. Heat exchanger and intercooler both suffer corrosion & should be kept a close eye on.
Overloading is the quickest way to kill one & they should be slightly under propped. Prop for 4600rpm wot & just never go there & your not far away & unbolt the wastegate actuator regularly and check the wastegate is free. When the wastegate sticks the engine performance actually improves because they overboost so folk think its going great when actually its destroying itself.
Run lightly loaded carefully maintained they are a gutsy frugal engine but neglect or flog one at your peril.

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[Steve10001]

What if I buy a turbo guage - or is there any sort of alarm i can get that will warning me if the turbo or pressure is acting up?

[Steve10001]

Originally Posted by beamishken

I've had a few of these in bits & yes they are the Isuzu built engine used in Astras etc. The block & head are the same, starter & iirc alternator from some vehicles fit. Gaskets & filters can be used from the cars. Crucially the pistons injection pump & injectors all differ so its not a straightforward swap. That said many folk have fitted automotive pistons & they do run, how long for is anyones guess. The life expectancy of those engines in a sports boat or rib isnt good so maybe cheap rebuilds are the way to go. Heat exchanger and intercooler both suffer corrosion & should be kept a close eye on.
Overloading is the quickest way to kill one & they should be slightly under propped. Prop for 4600rpm wot & just never go there & your not far away & unbolt the wastegate actuator regularly and check the wastegate is free. When the wastegate sticks the engine performance actually improves because they overboost so folk think its going great when actually its destroying itself.
Run lightly loaded carefully maintained they are a gutsy frugal engine but neglect or flog one at your peril.

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Steve10001
Join Date: Oct 2021
Posts: 4
What if I buy a turbo guage - or is there any sort of alarm i can get that will warning me if the turbo or pressure is acting up?
Any other tips to prevent damage?

Also, is there a better engine to swap it out with? ans what are the prices for an OK one in the UK. Im in Norway.

[Matt]

That's the old joke isn't it about stuff running the best it's ever run just before a blow up.

Originally Posted by beamishken

When the wastegate sticks the engine performance actually improves because they overboost so folk think its going great when actually its destroying itself.

[beamishken]

Originally Posted by Steve10001

Steve10001
Join Date: Oct 2021
Posts: 4
What if I buy a turbo guage - or is there any sort of alarm i can get that will warning me if the turbo or pressure is acting up?
Any other tips to prevent damage?

Also, is there a better engine to swap it out with? ans what are the prices for an OK one in the UK. Im in Norway.

A boost guage might help & regular checking & exercising of the wastegate is a must. Ensuring the engine isn't over loaded by being overpropped is a good start, Folk think ill fit a bigger pitch prop & reduce the rpm so its less stressed by not reving so hard when actually the opposite is true. Prop for 4600rpm wot but stay well below that and your good.
Not many conversion options to be honest at that compact size. A smaller volvo or yanmar diesel might go with some adaption, alternatively the 3.0 merc petrol is an easy swap. Or fit an outboard & gain a bigger, faster lighter boat. Not much advantage in the diesel nowadays unless your somewhere like the west of Scotland where petrol is hard to get.

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