I have a new Tower Hobbies .75 Ball Bearing ABC 2 Stroke Glow engine. While preparing to start it for the first time for break-in, I noticed the prop is hard to turn and seems to be catching. I've heard this can be remedied by heating the head with a heat gun. Please give advice on the best way to free up enough to get it to start.

Remember, a new engine is like a virgin, thus the reason for the break in procedure. Get it started, run it plenty rich and it will be easier to start in the future.

OH YEAH.Monster is right on. Once they are broken in the 75 is a power house. Let it burn a half gallon of fuel before you start asking it to make tons of power...........When you do start leaning the needle it turns into a monster(depending on what sort of model you put it on). Its a great engine for sure

The nature of the ABC engines is for a super tight fit, especially when cold, at the top of the stroke; the seal is formed by the top of the cylinder being slightly tapered. If you can't get it to start with a stick after 10 or so flips, use an electric starter. THe engine will build up enough heat so that the material will slightly expand, and starting it a second/third time etc. will be much easier.

I don't like the idea of using a torch/heat gun on an engine. Some hobby store proprietor just tried to sell me two engines that he said he had to do this to. They are built to be snug for a reason. If there is any premature movement of the material (expanding) not due to its own break-in process, you will start to lose compression and power.

Again, they are designed to be REALLY snug at the top of the cycle, and will break-in eventually.

If this is an ABC engine, do NOT run it rich for break in. Run the engine on the fuel you plan to use in it, nitro wise. When you get it started, run it at full throttle briefly, ( 10 15 seconds) and lean the high speed needle to a peak then richen it a bit (rich side of peak) about 500 rpm. Shut down the engine, let it cool (5-10 minutes). Repeat the procedure running at hig speed progressively longer several times checking the high speed needle to make sure it is not running lean. After several tankfuls of fuel of this, you can begin dialling in the low speed needle. IE set the high speed needle ( it should not change much from the earlier setting), reduce the throttle slowly to a point where the engine is running at slow speed. let it run at low speed for about ten seconds, then open the throttle. If the engine sputters and stumbles before picking up speed , lean the LOW speed needle a little at a time until it picks up speed reliably. If the engine stops when you advance the throttle RICHEN the low speed needle. I have found this procedure works for me.

While a blow torch or something which generates undue amounts of heat is a bad idea, using a hair dryer or medium heat gun is fine.

The heat temp barely gets over 160 this way, while normal operating temps are around 300, so you have an ample margin.

More important is to get the fuel flowing to lubricate the head, which this helps facilitate.

I do this merely to make the engine turn over so I can use an electric starter.

On some ABC/ABN engines such as the Tower .75, GMS .76 ( and up ), and larger SuperTigres, if I don't hit them with a heat gun first I'm apt to do damage to the engine.

Mine was the same way. I would feel like I got a bad one if it was not tight. I had to send it back because of the front bearing being bad but turned out to be the case overbored for the bearing seat. I never got a replacement. It has been backordered for 8 months now. What is up with that?

Sorry it was late. Torch bad, heat gun OK I'd still try it without the extra heat first, though. And yes, make sure you've got some fuel in the engine (holding finger over carb and spinning prop by hand until you get fuel in engine, which gives you both the fuel to get started and lubrication in the fuel), but not too much, which can make it even harder to spin.

http://www.towerhobbies.com/products...owg0175mnl.pdf

Here's a link to the manual for your engine; should have all break-in instructions, fuel requirements, etc. ABC's do break-in differently than ringed engines, so make sure you're reading the right section; some manufacturers have the instructions for both ringed and ABC's in the manual, so it's important to understand which one they are talking about.

I'm in the same boat. Need a carb for a TH .75 and have been waiting over 6 months. Starting to get pissed-off about it. I finally ordered an SK .90 carb for it.

I also need some parts for an AquaCraft .46 airboat motor. I'm using it on an airplane. It's made by Hobbico, same as the Tower motors. I think it's the same as a TH .46, but not for sure. Anyway, I can't get parts for it. I haven't been able to get parts for it in over 6 months and now they are slowly starting to list those parts as "Discontinued" Thats REALLY making me mad. If I want parts for this AquaCraft .46, I'll have to take the risk and buy TH .46 parts hoping they are the same engine. [:@]

I had the same problem and I loosened the glow plug and ran it rich.

I don't know about the Tower .75 but my Tower .61 came out of the box tighter than tree bark. I thought it was seized. When I read the instructions they mentioned that this is normal. I ran it in according to the directions and it has run fine except for one minor problem which was an air leak around the carb. I had to pinch off the fuel line to shut the thing down. A little sealant solved that problem and it has run great ever since.

Rufcut

Yup Tower Engines are manufactured in the same plant that SuperTigre and GMS engines are all made in.

Apparently after the acquisition of GMS and ST, the plant went through some major retooling.

This cased parts and new engines to be delayed, due to the ripple effect it has.

I've written and talked to Tower reps several times on this and they tell me that they are at the mercy of the plant deliveries.

They also said that the manufacturer is under a lot of pressure to get this stuff in this and next month as Tower is going into their prime time for RC.

I have had an engine and some parts on order since October of last year.

Their new catalogs shows all of these engines for sale so I'd expect that will suddenly start shipping the backlog...

I hope they do get them back in stock soon. Such a good and strong engine for a small price. Thanks for the information.

I agree I think letting an engine warm up naturally is the best way.i have rebuilt many hydraulic control valves and holding the spools in my hand caused them to swell and not fit into the bores, these pistons are tight enough as it is they have tight tolerances and heating them from the outside wont warm them evenly as if you ran them. also if you take a engine from inside a warm house to cold temp outside or vice versa let them set to adjust for the ambient temp they will be started in. most abc engines have a pinch fit at the top an electric starter is the best way to get them going until they get broke in.

Super Tigre says that Tower will have a LARGE order of engines in by April 1st.

Well that's great news.

It means that the Tower and GMS engines will also be in at the same time.

I'll believe it when I see it. I've been getting the same story
from them since November. The date for the Tower motors
has now been pushed back to late April. I'm not waiting on them any longer.


Mike Hammer

Well something is coming in... I just got a backorder shipping notification on some of my items...

The GMS engines just went to late April delivery. sigh.