Cruisers Forum

  This discussion is proudly sponsored by:
Please support our sponsors and let them know you heard about their products on Cruisers Forums. Advertise Here
Thread Tools Search this Thread Rate Thread Display Modes
Old 13-10-2018, 11:29   #1
Registered User

Join Date: Jan 2017
Location: Key West
Boat: 1986 Sigma 41
Posts: 192
White smoke and black exhausty fuel from Perkins 4.236

I have a Perkins 4.236 in my 1983 Dufour 12000 CT.

Today I drove it about 1.5 miles at what I think was normal cruising speed before I looked back and noticed it was billowing a fair amount of white smoke and leaving a trail of black ?diesely? slick in the water.

I immediately lowered the RPMs and the smoke and black diesel-ish stuff stopped coming out and all appeared well. I went back the 1.5 miles and tied up to our mooring.

I believe the problem is due to one of these fixes I made in the last week:

1) I installed a new throttle/shifter at the helm. This was an entirely new install, not a replacement, including new cables, etc.

2) I installed a tachometer about a week before that.

The tach may not be calibrated correctly but when I tested it before putting on the new throttle I would cruise at around 1750 RPM, idle at about 600. Today with the new throttle I couldn't get it much higher than 1500 RPM and it would start billowing the smoke/diesel when I got to that level.

Any ideas on what I may have done wrong on this install? I drove with this engine (without tach or new throttle/shifter) about 300NM a few weeks ago with no issues.

theglo is offline   Reply With Quote
Old 13-10-2018, 13:01   #2
Marine Service Provider
Steadman Uhlich's Avatar

Cruisers Forum Supporter

Join Date: Jul 2014
Posts: 6,105
Re: White smoke and black exhausty fuel from Perkins 4.236


I am no Diesel mechanic. But, I have listened to other sailors who like to troubleshoot their engines. Here are a few suggestions I noted related to white smoke:
  • If you were working on the engine controls and engine, check to make sure the decompression lever is not partially activated (it may have been moved when you were in the engine compartment).
  • Check the raw water strainer for obstructions and good flow.
  • Check the impeller.
  • Check for water in fuel or contaminated fuel.
  • Check for fouled fuel filters.
  • Check for partially plugged or blocked exhaust.

I hope this helps. I am sure other CF Members will add their tips too.

On another point: I really like the Dufour 12000 CT design.
Steadman Uhlich is offline   Reply With Quote
Old 14-10-2018, 19:03   #3
Senior Cruiser

Cruisers Forum Supporter

Join Date: May 2013
Location: Oregon to Alaska
Boat: Wheeler Shipyard 83' ex USCG
Posts: 3,375
Re: White smoke and black exhausty fuel from Perkins 4.236

White smoke is water or unburnt fuel.
Usually black smoke and soot is too much fuel. (Too much fuel for the amount of air) It could be the tach and the rpm you ran at prior to the tach are different and you're pushing the engine harder. The injector supplies more fuel, but the engine can't run any faster so isn't drawing enough air for the fuel to get a clean burn.

The shift cable is just moving a lever on the injector pump. It may be moving it farther. How did you determine your rpm before the new tach?
Injector pumps have a governor. When you move the throttle, you're really setting the governor. It sends more fuel if the engine is running slower than the setting and less fuel if it's running faster. The governor didn't change.
The other explanations would be something wrapped around the prop, a bad bearing causing drag, a partially plugged exhaust riser, fowled bottom and so on.
Lepke is offline   Reply With Quote

exhaust, fuel, perkins

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes Rate This Thread
Rate This Thread:

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

Similar Threads
Thread Thread Starter Forum Replies Last Post
Smoke, Smoke, Smoke that Cigarette ! bangkaboat Health, Safety & Related Gear 149 20-06-2013 22:41
Perkins 4-108 Black Smoke, Accelerated and Quit Phisher Engines and Propulsion Systems 1 13-11-2011 05:39
Yanmar issues... white smoke and black oily soot (exhaust) and engine smoke CS27 Engines and Propulsion Systems 3 14-09-2008 17:40

Advertise Here

All times are GMT -7. The time now is 16:29.

Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2023, vBulletin Solutions, Inc.
Social Knowledge Networks
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2023, vBulletin Solutions, Inc.

ShowCase vBulletin Plugins by Drive Thru Online, Inc.