SailNet Community - View Single Post - Why does my diesel not rev when in gear?
View Single Post
  #8  
Old 04-09-2012
shogan50 shogan50 is offline
Member
 
Join Date: Jan 2011
Posts: 83
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 4
shogan50 is on a distinguished road
Re: Why does my diesel not rev when in gear?

I have much experience with this engine and at least half of your symptoms. Disclosure: in the end, I raised the figurative radiator cap, removed my Volvo and inserted a Beta.

The starting problem and the reving problem may or may not be related. The starting problem is common and is most commonly a symptom of low compression. My MD7a (yours is also 7a if only 13 HP) wouldn't start on its own unless warm without starting fluid on all but the warmest summer days. (yes opinions vary on the advisability of this - not looking to start a thread)

After a $463 injector rebuild, I saw no improvement in performance in any measure. Not saying it applies to your case, just a data point.

The reving problem is likely fuel related. Start by checking your lift pump. Diesels need a way to get the fuel from the tank to the injector pump. They do this with what is called a lift pump, which is similar to a diaphram fuel pump driven from the cam shaft on most gasoline vehicles up to the 80's. To check is, put a hose on the output port going into a containiner and operate the priming lever. If nothing happens it is in your fuel system including possibly the lift pump itself. If you get something, release the compression lever, and crank. See if you get anything now. If not, you've confirmed it is upstream fuel system. If you do get regular pulses of fuel, then it is likely the injector pump, injectors. If it is down stream, try bleeding your injectors.

If up stream, replace fuel filters. Pour the fluid from them (there should be two or more) in a clear container if it isn't already the see through type. Check for water. Cut the filter in half with a pipe cutter or hack saw. Check for slime.

Check that your fuel pick up isn't plugged by above mentioned slime. Buy an outboard priming bulb and try to suck fuel from the tank. Water in the fuel, even if it doesn't make it to the filter, is fertile soil, so to speak for bacteria that eat diesel. That bacteria dies, forms a goo of bacteria carcasses, and plugs things up.
__________________
Islander 30 MKII "Sojourn"


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
Reply With Quote Share with Facebook