No revs in forward?

[Sailorchris]

My late model a4 will rev to 2000 in reverse and neutral, but only 1200 in forward. The throttle lever at the carb however shows the same travel.
As a result, I can't reach cruising speed. Immediately prior to this, the transmission was adjusted to improve performance in reverse. Is it possible that this adjustment is somehow binding the engine in forward?

[roadnsky]

Immediately prior to this, the transmission was adjusted to improve performance in reverse. Is it possible that this adjustment is somehow binding the engine in forward?

Very likely.

Here is a quote from the FAQ section of this site...

What would cause my engine to run with almost no power in forward, while it runs OK in neutral? It also seems to have more power in reverse than in forward.

This condition is usually the result of low power caused by something that was done incorrectly during recent engine maintenance.
The reason the engine seems to run better in reverse is because the reverse mode has a 1.7 to 1 gear reduction.

Here are some examples of maintenance problems that we've heard about:

Three to five times each year, spark plug leads were found to be installed in an improper sequence following a tune up!
Cylinders 2 and 3 can apparently be reversed, and the engine will run fairly well in neutral, but will have practically no power in forward.
According to one caller, his plug wires were reversed for an entire season before he found the cause of his power loss.



Another recent maintenance "oops" involved a minor repair of the exhaust system which required that the manifold be removed. On reinstallation, the old gasket was improperly installed, resulting in intake leaks and very poor power under load. 



Assuming that there was absolutely nothing done to the engine since it was last running OK, check the following areas for potential problems:



1) Check for something hanging on to the prop.


2) Check basic integrity of the engine by a quick compression check.
If compression is weak in two adjacent cylinders, or water is observed in any of the combustion chambers, the head gasket has probably failed. 


3) Check for proper carburetor function.
Normally, an Atomic 4 will accelerate almost "explosively" as you flick the throttle forward. If there is any hesitation or mild backfiring, a lean condition caused by dirt in the main jet is the most frequent cause.
In most cases, a problem related to a fuel issue will manifest itself in neutral as well as in forward, but in mild cases, a lean condition might be missed in neutral, but will surely show up under load.


4) Check for proper ignition.
As in the case of subtle lean fuel mixtures, there are subtle ignition problems that can show up under load but not necessarily in neutral.
In this category, plug condition is the best indicator.
If one plug is noticeably blacker (or oilier) than the rest, look for the relatively few things that can affect only one plug, such as the plug itself, the plug lead, or a cracked distributor cap.
If all the plugs are badly fouled, check things that can affect all plugs, such as a loose condenser, badly worn points, shorting coil (or oil leaking from the coil), cracked distributor cap, or a bad coil lead.

[Al Schober]

Transmission adjusted in reverse. Now won't run well in fwd.. Well, perhaps if the transmission were adjusted so tight in reverse that it was staying there in fwd?
The reverse cam moves whenever you move the shifter. The action shifting into reverse is well known. Well, it's possible that a fat part of that cam is tightening the reverse band when in forward.
I would recommend opening the cover on the reversing gear and seeing whats going on. Disconnect any remote shifter and look inside the cover as you move the lever manually. When you shift into fwd, does the cone move aft and engage the fingers properly? When you shift to reverse, does the cone move fwd and become hard to move just before the cone contacts the fwd adjusting ring?
Take some pictures. Might help.