No power forward/Power in reverse

[forcenine]

Don, et. al:

Having fixed the overheating problem, I can now start to isolate my power problem hopefully. At first I believed it was all related to poor compression which I've been working on w/MMO. But I my figures are high enough to suggest I have 3 working cylinders which should be enough for some power.

What is happening is I am fine in idle and appear to have throttle in reverse but in forward gear, there is little to no throttle. If it does not die immediately after going out of neutral then it will shortly and pushing on the throttle produces no rise in power. I have been told to check out transmission gearbox problems about which I know nothing.

It's not the (new) Indigo prop, not idle mix or timing, not carb float, etc. new rotors, condensor, probably not shaft/stuffing box related since this was freed after being stuck at a December haulout. Reverse might have a bad sounds, I can't tell. Choke has no effect on problem.

I need some ideas to start troubleshooting. Thanks.

Lisa

[bayareadave]

Reversing whine

The Atomic 4 makes a characteristic noise when put in reverse. It sounds like a whine with a little bit of clatter. There are others who will give good advice on the power problem, but you may want to clarify a couple of things: 1) It powers normally in reverse? For how long?, and 2) Can you rule out a linkage problem from the lever to the carb?

[policecentral]

Low Power in Forward

I had same exactly same problem. Would run and accelerate in Rev, but die or low power in Forward. I too had low compression, but in two cylinders, not just one.
I suspect this is your problem. The A-4 running on FOUR cylinders only puts out a few HP at low RPMs, and it takes less power to run in Rev than Forward. So you have barely enough in Rev, but not enough to keep running in Forward.
Check out MM site for what to do about fixing compression. It might be relatively easy (hopefully) or might require head removal and valve job. Of course, Don would always recommend Marvel Mystery Oil to see if you are lucky. Remove the plugs, squirt some MMO in the holes (aiming toward the manifold) and let it sit a few days. It might loosen up a stuck valve.

I fixed mine by replacing the A-4 with one purchased on Ebay.

Jim
Ranger 30 Northern Light
Savannah

[David Masury]

I can tell you that I have had the exact same problem.....and fixed it. Before you start sumizing that the engine is gone... do a compression check. simple enough and it will give you an indicator. Low compression in two adjioning cylinders may mean that the head gasket is leaking between those cylinders, or valves may be sticking open, or the worst case you may have a burnt valve or two.

The headgasket is a simple few hour repair and you should be able to do it in the boat.

Sticky valves can be accessed from the plate behind the carburator... if that is the case, then a liberal dosing of MMO or ATF will free the valve(s)

If you have a burnt valve or two,,, which was my circumstance, then pulling the head and manifold, then tackling the valves is a bit more work, but you should be able to do it with Don's A4 Manual.

Get back to this forum with what you find and I am sure that you will get enough help to get back the power.

David

[forcenine]

Compression

Gentleman,
I have done many applications of MMO and compression tests with slight improvement although until now (when I fixed overheating problem) I have not been able to idle for more than 5 or so minutes. Now I can. Cyl One-av 105), Bad cyl 2 (av. 63), Cyl 3 and 4 (av. 78, been 80 before).

The head cannot be pulled without taking th e whole frigin engine out frontally. There is no milky oil if that is characteristic of blown head gasket. I exposed the values with cover off when my manifold was off and sprayed alot of carb cleaner on values/springs but don't know how to check clearances nore can I see the tops of the values (can I?). I'd like to be able to look at the exhaust values but don't see how I can through that opening.

Short of values/rings, could this be a symptom of gearbox problem? I'm not sure how to even check my transmission fluid right now.

Lisa

[David Masury]

I can pretty much tell you that it is not the transmission....unless it is very much out of adjustment and even then I am not sure that it would cause the symptoms that you have expressed. The one exception might be is that the reversing band is too tight and is conflicting with the forward motion.

You transmission is lubricated with the engine oil, thus if you have sufficient engine oil and good oil pressure the transmission is well lubed.

Your compressions numbers are a good indicator that you have a valve issue... a valve job is neither difficult or expensive... and if your engine does not burn oil, then pulling the engine forward, doing the valve job and re-seating the engine is not a difficult job... if you do not feel comfortable doing this work, then any mechanic would be able to do this job wihtout too much fuss.

David

[Don Moyer]

Lisa,

Nothing in your prior reports indicates to me that you have any issues with your transmission.

I think the best chance you have to gain additional improvements in your compression is to put 8 to 10 ounces of MMO per gallon of fuel in your fuel tank and run the engine long and hard under a normal cruising load. My instinct is that you're spending too much time idling. If you don't trust the engine enough to go for a ride, check your dock lines and pull on them in the slip for a couple hours at a good high cruising power setting, checking compression every hour or so for a positive trend.

If, before you do that, you can fight through the process of removing your valve cover to check the valve clearances (.010" for intake valves, and .012" for exhaust) it seems to me that you will have done all the essential steps in improving compression without heavy maintenance (a valve job being a good first step).

I'm attaching a guide to help you with the valve adjustment process. Be sure to stuff small clumps of rags into each of the four holes in the floor of the valve chamber so as not to allow any crud to fall down into the crankcase.

If you can't find volunteer assistance, checking the valve clearances is probably important enough to justify paying for a bit of local mechanical help if you find the prospects too daunting to do it yourself. If you have decent access to the valve chamber (just behind the carburetor) a competent mechanic should be able to check your valve clearances in approximately 1 to 3 hours. As a matter of perspective, valves can be checked and adjusted with an engine on a workbench in approximately 20 to 30 minutes. In some cases, poor access makes valve adjustment virtually impossible on a boat, so don't let yourself be drawn into a huge bill; ask for a quote before proceeding.

Don

[forcenine]

Idle is only option

Don,
Thanks for that. Unfortunately idling is my only option other than reverse. It just keeps dying in forward gear. We've revved it enough to get it to live in gear for a couple of minutes but then it dies. I have also put MMO in the fuel.

I've seen some other power notes about coil problems, new plug wires, etc. (already bypassed oil safety switch as test). It just seems from what I read, that 2 cylinders at 79 and one at 105 should be enough to give me more power than that. But maybe not.

The only guy I can find that works on A4s here, i don't think will work on values in the boat. And he wanted big bucks even in his shop-can't remember how much off hand. I'm concerned that it could be a waste of money if it is actually rings.
Lisa

[Don Moyer]

Lisa,

I'm sure I recall you posting your compression values earlier but I can't seem to find them. Are they all over 80 psi by this time?

Also, while in neutral with the engine fully warmed up, can you take the throttle and "flick" it forward as quickly as possible without the engine hesitating?

In performing the acceleration check, be sure to not allow the engine to rev to too high an RPM. The value of the check is not whether the engine will get to any particular RPM but how quickly it accelerates without hesitation. An Atomic 4 should accelerate "explosively" (sorry, but that's the only word I can think of during telephone conversations to describe the throttle response we're looking for). Assuming that compression is OK on all cylinders and the ignition is strong and in proper time, any hesitation in the acceleration check would normally indicate some restriction within the carburetor - frequently in the main jet itself.

Don

[tenders]

You mention that it's possible for you to get it into forward gear for a few minutes before it dies. How sure are you that your fuel pump is up to snuff? A primer bulb between your fuel tank and fuel pump to assist a marginal pump would be a cheap, easy, and potentially useful diagnostic.

[forcenine]

primer bulb

Tenders-
I did put on a primer bulb on a while back in order to get it to start earlier on. It doesn't even seem to need it now. I can start fine in neutral. Electric fuel pump was replaced and sounds like it is working.I truly think I deserve a break after all I've done-don't you? HA.

Don,
Cyl 1 is averaging 105, Cyl 2 and 3, 78-80. Only cyl 2 is really bad at 64. I'll work on it this weekend too but I am far from explosive in forward gear-lucky to get there without dying, But OK in reverse.

One year ago when I acquired this $1.00 boat (HA) a mechanic did not get compression and SOAKED cylinders in RISELONE and it came back although I knew nothing then and do not remember those numbers. But he led to to believe it was going to me OK.
L.

[Don Moyer]

Lisa,

The acceleration check which should have had the "explosive" response was
intended to be accomplished in neutral. Did you try the acceleration check
in neutral?

Don

[forcenine]

acceleration

Don,
The carb has been opened and rebuilt, main jet checked, floats checked. Everything about the carb should be OK. I'm not totally clear on the acceleration test. This weekend, since I could not go into forward gear without dying, I tried to run it ihard in reverse gear but I began to experience the same problem as in forward albeit not as pronounced--gradual loss of power until death do us part. (I think I've been there) I've found only one mechanic in my area that will do a value job if I bring it to him without the head for $300. Is that in the ballpark? Is it crazy not to do pistons or other work if I take it out for values? I can't afford it.
Lisa

[Don Moyer]

Lisa,

Let me try again. The acceleration check to which I'm referring is an acceleration check in NEUTRAL. Do not go into forward or reverse. While in neutral, flick the throttle forward as quickly as possible. Report back on whether the engine hesitates, backfires, or whether it accelerates quickly to a high RPM which requires that you quickly retard the throttle to avoid overspeeding (over 3000 RPM or so).

Don

[forcenine]

throttle up test

Don,
I finally performed the acceleration test in neutral as described. I do not have any hestiate or backfiring in neutral. It does throttle up explosively and needs to be brought back down in idle. A new development is that changing out sparkplug wires and plugs allowed me to actually run for 20 min plus in reverse, stable. Before the new wires/plugs, reverse was acting rather like forward-loss of throttle and dying--only not right away (I understand about reverse not requiring as much power). Forward though, even after the new wires/plugs still will not cooperate. Still thinking valves?
Lisa