W21 NO POWER

[cdells]

Hello everyone,
I bought a 1983 Hunter 34 earlier this year at Harrington Harbor in Maryland to learn how to sail. Shortly after taking the boat out I noticed that there was very little power from the engine when the boat is in gear. Top speed is about 2.5 kts and the engine regularly bogs down and dies. It always starts right back up but with little to no power...makes docking a pain because it takes for ever to actually get the boat to maneuver. It also seems to be leaking a fair amount of oil...going to the bilge. I had a local diesel repair guy look at it and he just told me to repower, won’t tell me what’s wrong or why. I get that it’s an old engine but I’m just trying to get off the dock and go sailing...I don’t want to drop 8k on a rebuild.
Any suggestions on where to start my troubleshooting? My first thought is the fuel but the filters look good. Could the oil loss be tied to compression loss somehow...I don’t see oil anywhere on the top or sides of the engine...it looks like it’s coming from the back rear of the engine.

 

[kloudie1]

That is the Westerbeke engine, I am thinking?
you may have fuel starvation because of a plugged tank vent or trash in the little screen on the tip of the pickup tube inside the tank. Check for plugged vent by loosening the diesel filler cap. If engine runs normally, ya know vent is not venting. Tank pickup can be removed for inspection and the little screen removed to let the filter catch stuff.
Set the valve clearance ..
the oil may be from a leaking rear main crankshaft seal.
lack of compression can make low power, but usually makes an engine very hard to start.

 

[kappykaplan]

Have you looked at the prop? Barnacle fouling has been very bad on the Chesapeake this year. What RPM are you getting?

 

[kloudie1]

Another thought.. that engine probably has an electric fuel pump which may have a filter in the pump itself.. That one may be plugged, and is often overlooked.. The pump itself could be weak, or the little electrical breaker on the engine could be failing..

 

[cdells]

This was the prop before the bottom was cleaned...RPMs are good at idle or neutral but drop down down to between 1k and 2k with no change in throttle...then it dies

 

[cdells]

Thanks kloudie1, I’ll add that to my troubleshooting list for this weekend. Yes it is the Westerbeke 21 engine

 

[Davidasailor26]

My guess is that is that it can be fixed up without needing a repower. How does it start when cold? Any excessive smoke under load? If those are ok then it probably has decent compression, and the issue is just somewhere in the fuel system. The leaking oil might mean it needs a new seal somewhere - you’ll need to track down where it’s coming from. Also, the engine should sit in its own pan that doesn’t drain into the bilge, to keep any oil out of the bilge water, so you might want to look into that at some point too.

 

[kloudie1]

The "runs OK at idle but dies under load" thing is a classic fuel starvation symptom.. especially if it starts OK.. I'd chase the fuel filter in pump first (if indeed it has one) then tank pickup .. usually, an air leak on the pump intake side would make it hard to start; also assuming that the filters and lines were all bled of air..
Good Luck !

 

[FastOlson]

All helpful suggestions, and good luck to you.
Is the engine a 2 or 3 cylinder Yanmar?

Also, double check your survey for engine running notes. While a separate engine survey is best, many surveyors will basically check out the engine. (A surveyor that I have known for years is also a mechanic in a former career.)

 

[Benny17441]

80% of the auxiliary diesel engine problems are fuel related. Start at the fuel tank vent and make sure it is clear of any debris as critters love to set nests in laid up boats. Check fuel flow from the tank to the water separator, The fuel flows by gravity but a clogged screen in the pick up tube might reduce or impede flow. In the case that the tank may be found to have excess sediments, polishing of the fuel may be advisable. Drain any water from the water separator and if an excessive amount of water is found, replace the filter. Run the engine and look for fuel leaks along the entire path of the fuel lines filters and pumps; where fuel leaks out with the engine running air can leak in when the engine stops. Clean all engine surfaces and identify source of the leaks. If air in the fuel lines is suspected bleeding the air out of the lines may be necessary. Check the fuel pump for leaks and for electrical Voltage and continuity. If an intermittent electrical failure is found, replacement would be in order. Check idle RPMs as low RPMs can cause the engine to stall. They should be between 750-850 RPM. You can get a feel for the engine compression by checking the blow by pressure. Run the engine at idle, remove the oil fill cap and hover the palm of your hand over the opening. You should feel a slight pressure from each revolution. This is compression leaking past the piston rings. If a strong thump is felt it could indicate the rings are worn and the engine compression is low. Like Kloudie indicates the fact that the engine starts right up does not point to excessive low compression. Condition of the fuel would be another factor to check; old, stale or contaminated fuel could produce uneven engine run. Also check the engine Air Intake Tube for any obstructions like a clogged air filter. Blockage in the exhaust system should also be considered, an abstruction in the mixing elbow, muffler or discharge thru the hull port. Can't remember if on the h34 the discharge port is above water but if it is critters also tend to nest there. The general symptoms sound like fuel starvation, it starts at higher RPM where the demand for fuel is larger and eventually progresses to the lower RPM as the fault deteriorates. Find what may be creating a slow flow, whether blockages, air, faulty pumps, clogged screens or filters and you will resolve the problem.

 

[JoeWhite]

My similar problem turned out to be a blockage inside the primary fuel filter bracket.
Visit Sail La Vie | 1999 Catalina 36 MK II for more description and photos.
Haro.

 

[cdells]

Wow, thank you all so much..great advice here. I spent most of the day getting access to things and doing some troubleshooting. I took the pickup tube out and took the screen out to see if anything would show up in the primary filter. Clear the pan really good with a dergreaser and then put oil pads down to see if I can pinpoint the oil leak. As I was cleaning out the pan there was a fair amount of coolant mixed in as well...does that point to anything? In any case, after my troubleshooting...it won’t start. There doesn’t appear to be any fuel coming out of the fuel pump...not even sure if it coming out of the Racor to be honest. I ran out of daylight and patience so I packed it up for the day. I’ll keep at her...just gotta go slow

 

[cdells]

So I got back out there this weekend and went through the fuel system from tank and vents up to the injectors. I cleaned connections and vents and disconnected and reconnected things but didn't see a real problem. In any case I took her out for a spin and had no issues with rpms or starvation! I could maintain 3000 rpms and never bogged down....but the engine overheated after about 20 minutes. I am guessing that either the impeller is not pulling in enough water or the cooling system is otherwise not in order. I am good with the impeller change out but this thing has a very involved looking cooling system....what needs regular maintenance on these Westerbeke systems?

 

[Boatkeep]

Hello,

For anyone reading this is the future here is an article I wrote with a few simple diagnostic tests you can use if your boat engine starts, runs a little then dies after a few seconds.


Hope this helps someone out!

All the best and happy boating,
Boatkeep: Free online resources for boat owners