NitroJoe1986

I just replaced the engine in my earthquake 3.5 with an SH M21 P3 engine. Only difference is the cooling head is slightly bigger on the new engine and it had a different crank than the stock engine. I tore down the stock engine and swapped the crank into the new one and made sure all bearings, bushings etc were in where they need to be and everything is tightened down with Loctite where needed. I have the carb set to factory settings with about 1mm gap for idle, primed the engine, put the igniter on the glow plug but there doesn't seem to be any engine resistance to start it. I checked my plug and it glows bright.

What am I missing? I have blisters on my fingers from trying to get it to start the last few days

Redcat James

Is the new crank exactly the same as the old crank? Did you installed the one-way bearing correctly onto the back of the crank?

NitroJoe1986

The new crank is the exact same with the exception of the longer shaft outside the case and isnt threaded completely. I removed the new crank and put the stock crank in the new engine since it was still like new. It fit perfectly with no play and everything lined up perfectly.sleeve is installed in the proper position clutch and clutch bell are still almost new since it hasnt run much since I put them on.

NitroJoe1986

To clarify the difference with the crank the left with the shorter shaft threaded to the end is the stock style and the one on the right is the style of the crank the came in the new engine. Both engines are SH .21 and both have same crank case size as far as length, width and height so I don't feel its a problem with the crank. These pictures are just examples of the different shafts, physical appearance of both cranks that would be inside the engine appear to be as close to being the same as possible from what I could tell looking at them. I was sure to closely check them both and compare before attempting to put the old crank in the new engine

Redcat James

Did you installed the one-way bearing correctly onto the back of the crank? It may be an illusion but the the hole size on the fuel intake look different?

NitroJoe1986

I installed the OWB so that it fits into the backplate so the notched side is facing the crank. The actual cranks are identical including the intake, The pictures are just something I found online for an example of the output shaft difference.

Redcat James

And the pin on the crank is in slot for the owb?

NitroJoe1986

I feel like an idiot for not checking this first but my problem was that 3 of the 4 head bolts were a little loose. I thought I tightened them down enough from the start but I guess not. Im scared to use Loctite on them because I fear I will never get them out again if needed. Engine is now running well although I have another issue now....

My son got his hands on it yesterday while my sister was babysitting him and she let him play with it thinking it was a toy... He ended up snapping the throttle servo horn on the end where the throttle linkage connects. The nearest hobby shop is a 6 hour drive from me so I cant just go buy a new one for a few dollars so ive been trying to figure something out that will hold it. Epoxy wont work as it appears the fuel eats through it or something and it just peels off after you get the engine running a few mins. I don't feel super glue would have a strong enough bond. Any suggestions? I really don't wanna pay $20 to have a new servo horn shipped if I absolutely don't have to