Hello Mates:

I just came in from running the MVVS D7 and here are the results:
Weather 42deg F or 12deg C. Just stopped raining.
Fuel: Davis with 6 oz. of castor oil/gallon added it is at least a year or two old but kept in the original screw capped metal gallon tin.
The contra piston was lowered until it was very close to the piston but in no danger of hitting the piston.
After priming through the venturi, choking the venturi. and placing four drops of fuel in the exhaust port, the engine started.
The prop was a Cox gray 8x4 Finger Slicer!!!!
The nv was adjusted for max speed and then opened slightly. The compression was backed off to a point where it began to slow down.
All was well but the exhaust goo was black????? Same fuel that I run I my ST G20/15D. The ST produces a clear exhaust residue?????
Is there something wrong with my MVVS like aluminum is being rubbed off of the engine internally? This is the only Diesel that produces a black exhaust residue. ????

The restarts were obtained by slightly increasing the compression from the best running setting. choking the fuel Iine to get the fuel to the nv and placing a few drops of fuel into the exhaust port. The restarts were not all that easy but easier than a cold start.

Should I add a bit of ether to my fuel as some of it may have been lost over the year(s). I was thinking of adding about 30% ether to the fuel and see if that aids starting. I will mix a small batch to see if indeed I need more ether in my fuel.

Comments/suggestions?

Tia,

franchi

franchi

I do not have experience with small diesels like yours. My smallest engine is a OS 40FSR and the largest is a ST 4500. In all I have about 15 diesel engines. From my experience black goo is a sign of over compression. I would suggest backing the compression a bit while slowlyclosing the needle until a good power is obtained with slightly grayish exhaust.
As to fuel, I have about 15 gallons of Davis's fuel that are over 20 years old and run like champs. If you have Davis's fuel, my recommendation would be to use it AS IS. Bob knows very well what he is doing.

MVVS .15 Diesels are renouned for running "dirty" as they run in. If you're sure it's not overcompressed then don't worry too much, a friend of mine describes the dark exhaust as being due to them using "dirty" cast iron in the piston.

MVVS .15 Diesels are renouned for "dirty" exhaust as they run in. If you're sure it's not overcompressed then don't worry too much, a friend of mine describes the dark exhaust as being due to them using "dirty" cast iron in the piston.

I agree if the fuel works as is in the ST G20-15D, leave it alone. Trouble with storing diesel fuel in metal containers is usually rust blooms in the tin plate. Can you normally smell Ether where you store your fuel? If not you don't have a problem.

Hello Mates:

I have learned to accept the black exhaust residue from my MVVS D7 as being "normal." Other than this characteristic, this engine is a pleasure to use. It starts very easily, easy to adjust and has adequate power.

Thanks for all of the help,

Franchi

Can anyone advise what model this 2.5 c.c. MVVS is?

Hello Fiery :

Wow! That engine is a mystery to me! What size and model is it and how is it running with your finger over the intake?


Good luck,

Franchi

I think it was simply called DR but I don't have any of these myself.
(i.e. it would be an MVVS 2.5DR engine)

Derek, you mystery MVVS is a 1974 DR model.

Thanks Peter. Much obliged. My example is in superb condition. It came from Wayne Wilson.

I had one of them, but was never really sure I was getting it to perform to its potential, so I sold it.

Life's too short ti mess with engines that don't meet expectations.

Mine is definitely a MVVS 15 DRR and differs from yours Fiery, in the exhaust stub being machined for an o-ring and mini pipe

I don't know why this site has made it so difficult to upload photos ...

edit

I bought the following about 15 years ago when I was working in Germany, a clean sweep at the time.

MVVS 15 GFR
MVVS 15 GRR
MVVS 15 DFR
MVVS 15 DRR

Pics are easy enough, in your reply, "Go Advanced", then click "Manage Attachments"

Ay yes, I see now. It's just the mobile version of the site that loads by default on smartphones that doesn't allow photos

According to admins, "the tech team is working on that". That was over a month ago. They claim they're fixing many other bugs too. I don't hold my breath.

I just view the site fullsize site on my mobile devices.

Let's see if the photo uploads

The MVVS .15 DR can be made to go very well. I suspect that the ones that do have possibly recieved a Rossi mk2 piston and liner and some timing and alignment changes. Greggles47's was sold to a chap in the UK who may have used it to win c/l British Goodyear racing at the UK Nationals.