View Full Version : Yanmar Turbo Lag

02-04-2009, 10:03 AM
"Our company has 2 31 Ocean Pro Parasail Boats that in the last 2 years were repowered with Yanmar diesel 6LPA-STZP2 315 hp motors. We run Mercruiser bravo 2 outdrives with a 19 inch prop, and the problem we experience is a tremendous turbo lag when we go power up for take offs and landings. The lag is not bad when the parachute is not in the air, but there is much more resistance on the motor when it is in the air. We had 21 in props on the boats, and then went to the 19 in, and the problem got better but is still unacceptable for our purposes. Any ideas on what might help us with these motors? Thanks for your help!!!"

02-04-2009, 11:51 AM
Try these guys, they are great! I purchased my 3 blade from them and talked them several times about what I was doing and what was best for my Morgan sailboat.
General Propeller, in Bradenton, FL
http://www.gpcprop.com/ ("")

Capt Steve
Powell's HIGH LIFE
Morgan 382
Rochester, NY}"

02-04-2009, 10:09 PM
"Hi Mike, Best to contact Yanmar in Adarsville Georgia for some answers. Talk with their service deoartment. I recall them mentioning a few years back they were concerned with the para-sail application due to no to a sudden full or over load on the engines and drive.
All the best, Ron"

01-24-2012, 06:11 PM
I am having the same problem with my Parasail boat over here in Australia.
where you able to work out what the problem was?

01-24-2012, 06:15 PM

I am having the exact same problem with my yanmar 6lp in my parasail boat over here in Australia.
where you able to work out what the problem was?
Or does anyone else have any suggestions?

01-24-2012, 09:28 PM

I am having the exact same problem with my yanmar 6lp in my parasail boat over here in Australia.
where you able to work out what the problem was?
Or does anyone else have any suggestions?

Better to start a new thread.

When was the last time the turbo was inspected for wear and cracks? When was the last time you ran a turbo wash through your turbo? When was the last time you ran this engine up against the governor?

01-25-2012, 06:28 AM
I Have not had the turbo inspected, It is a parasail boat which i use everyday. The problem started approximation two weeks ago and has progressively gotten worst. I removed the inspection plate on the turbo and the linkage on the waste gate and check that it was not sticking. everything was moving freely and apart for a little carbon the turbo seemed to be in good condition. My Boost indicator light did come on a couple of weeks ago which i believe was indicating that i had low boost pressure. I inspected the engine for any problems a and found the a wire had come loose on a sensor which i replaced and since then have not noticed the boost indicator light come on. The turbo seems to be working fine when it actually kicks in, it is just taking 3000rpm before it kicks in instead of 2000rpm.

I have not used a turbo wash yet, actually have never herd of it.
It has never been run against a governor, what would be the purpose of this? what would i be looking for?

01-25-2012, 09:29 AM
Copied from a Yanmar help page:

TURBOWASH the turbocharger.
TURBOWASH is a genuine Yanmar part, don't let any ignorant dealer tell you otherwise. The dealer should be repacking the TURBOWASH from the large container and selling it in 250cc / 8oz bottles, not fitting you up with a lifetime supply!

Thunder down the harbor with the engine at 75% load and spray up to 25mls of TURBOWASH into the air intake over about 15 seconds.
Wait a bit
Spray an equivalent amount of clean fresh water into the air intake
If it doesn't come clean, try up to 4 times.

In some manuals Yanmar recommend using dish washing liquid if TURBOWASH is not available. In my experience it doesn't do the job whereas TURBOWASH cleans right around the bend. I can only recommend the proper product, it really works!

I have replaced a few Yanmar Turbos because of the Lag. They were replaced because the housings were cracked. When I looked at my first Yanmar turbo it felt fine and looked good, I pulled it off anyway and took it to Mack Boring Here in NJ. They fully inspected the turbo and showed me all the damage I could not see or feel. They asked if this boat was run at slow speed a lot, and of course it was. That is when they handed me a service bulletin about trolling with the 6L engines and how you need to run them wide open for a few minutes after trolling for a while. It cleans the turbo.

I would pull the turbo and have it inspected. It comes off fairly easy. You will need a long extension and a swivel socket to get to the lower mounting bolt


10-16-2013, 09:58 AM
I have 4LHA-STZP motors in my 34 foot Rinker EC. Can I change the turbos to get a little more power? Any other ideas?

10-16-2013, 08:45 PM
What is the problem with your set up? Taking a little to long to get on top of the water?

Chris Atkinson
07-21-2015, 08:12 PM
Hi Chris I'm and engineer in the UK and have a problem with a 6LP-STZE Turbo. When under load it will not rev higher than 1500rpm, but run free up to 4200 rpm , There,s no smoke and no noise from the turbo at all, the engine has been stationary for sometime and only recently brought back in to service. it ran very well first time out, but we had a problem with the Bravo 3 leg and had to rebuild it, when we put the boat back in the water we had this turbo issue. any thoughts thanks Chris