|
| Author |
Message |
    
johnhamilton
Visitor
| | Posted on Sunday, February 26, 2006 - 11:55 pm: | 
|
My Perkins 4.108 has become difficult to start, & when it does finally start it is running unevenly, struggles to build up revs & surges back & forth mildly. I have ruled out a fuel problem, new filters have been fitted etc. there seems to be more blue smoke exiting the exhaust. I fear the rings may be shot....has anyone got any ideas? John Hamilton. |
Darel McCormick
Member
Username: sardog
Post Number: 4
Registered: 02-2006
| | Posted on Monday, March 20, 2006 - 08:42 pm: |
|
The first thing I would ask is the smoke really blue or more white. Generally, the rings will wear at an even rate and cause a general lack of power. You'll get white smoke at idle (low compression) and black smoke at less than full load conditions (unburned fuel). Hard starting will also factor in. Even with these symptoms, the engine usually runs smooth and does not surge. I would start with the simple stuff first. Clean the air inlet screen. Make sure your fuel stop is in the fully retacted position to the mechanical stop (full run position). Double check all fuel supply hoses and fittings including the primary fuel filter gaskets. If this engine gets any air in the fuel it will run like crap. Then remove the valve cover and crank the engine with the fuel stop engaged and observe the valve action. Make sure they are all operating smoothly with no sticking valves. Then renew the injectors with a fresh set. If this doesn't do it, you work your way back to the injection pump. Beyond that you could have burned valves, bad rings, excessive wear etc., all requiring total overhaul. You didn't mention the engine hours or frequency of use, which could be useful in diagnosing the problem. Good luck, Darel. |
Dwight Brooker
Member
Username: sailmaster
Post Number: 25
Registered: 05-2006
| | Posted on Wednesday, July 19, 2006 - 07:39 am: |
|
I have 11,000 hours on my 4.108. If maintain right they will last a long time under the most extreme conditions. Having said that, I had a similar problem a few years ago. After rebuilding the injectors and injection pump the problem was gone. The cause was bad fuel. I picked up diesel fuel at a marina in Pensacola, FL that had been treated with “Valvtect” Fuel Micro biocide. The problem was that they had no idea how much was added and they did not tell me and I added more. It turns out that they used 10 times the recommended amount and it dissolved all off the rubber seals in the injector pump, fuel lines and rest of the fuel system. The rubber turned to mush and plugged the ports and caused excessive corrosion in the pump. The symptoms were as you described. I am not saying that the cause of your problem is the same but the operating condition is. I hope this helps. |
Wolfgang Schulze
Visitor
| | Posted on Friday, April 27, 2007 - 12:55 pm: |
|
Hi, I own a 4108 M Perkins,
On the last time i`m rnning out of fuel, without aparently reason.
Did you know, what is the consumption rate , on 1.800 , 2000 , and 2.200 Rpm ? |
Dwight Brooker
Member
Username: sailmaster
Post Number: 48
Registered: 05-2006
| | Posted on Saturday, April 28, 2007 - 06:16 am: |
|
You should be using 1/2 to 1 US gal per hour. |
RavenTom
Visitor
| | Posted on Tuesday, February 19, 2008 - 01:40 pm: |
|
As Daryl says, be sure you have tightened and checked the fuel lines, especially the return lines. I didn't pay attention to the returns thinking they were less important, but this engine routs the returns back through the secondary filter, which means that air goes back through the injector system to cause surges in rpms. After tightening and replacing seals, rpms smoothed right out. |
Richard Grimshaw
New member
Username: grimshaw
Post Number: 1
Registered: 09-2009
| | Posted on Tuesday, September 15, 2009 - 08:11 pm: |
|
Perkins 4108 I have just completed a major overhaul of hoses seals and pumps. After bleeding the fuel system the engine started and ran well. After stopping and then attempting to restart, it would not start, so I re- bled the system. It started. This pattern has continued. I have checked all connections - they are all tight. Before I did the work on the engine it started very well, with very little throttle.
Note when it is running it runs smoothly with no sign of air in the fuel. Anybody got any ideas? |
Richard Grimshaw
New member
Username: grimshaw
Post Number: 2
Registered: 09-2009
| | Posted on Tuesday, December 01, 2009 - 03:38 pm: |
|
I thought I would update you on fuel line air problem. I eventually solved it by replacing all the rubber fuel line olives. In particularly there were three olives on the return line from the injectors, that when replaced seemed to solve the problem. The olives that I replaced were probably the original, and had become "hard" and had "moved" during the engine overhaul, resulting in an imperfect seal even when tightened to the maximum (note there was no fuel leak, but as my new online buddy Jim tells me that air molecules are smaller than diesel molecules). Moral of the story is to replace all seals and washers particularly when old. I also replaced the copper banjo seals on the secondary fuel filter (one attached to engine) with metal washers that has an inbuilt rubber seals. I am sure that these helped too. |
|
|
