Boatman
Active member
- Joined
- Nov 2, 2009
- Messages
- 35
- Fluid Motion Model
- C-24 C (Sterndrive)
- Hull Identification Number
- RFB02664D593
- Vessel Name
- TUG-ALONG
😀 Well, guys now that the winter wx is in full swing, batteries seem to be the hot topic, no pun intended. I am offering this info in case it is helpful to others. There will be some follow up postings as this hard starting issue unfolds. My 3GM30F built in 93 only has 550 hours on it if the hour meter reading can be trusted. I recently bought this R21 which was originally known as "Sea Spirit" and now answers to the name of TUG-ALONG. She was a trade in. The engine is becoming hard to start. I suspect its due to multiple issues. One is the colder temps. A second reason is that there is only one battery, a Costco deep cycle with 550 CCA series 24. This battery could start the engine in warmer wx but will barely crank the engine now that it is cooler, 40's-50's. My understanding is that if there is not enough capacity to properly engage the starter and crank the engine with authority, you can wind up damaging the contacts in the starter by causing intermittent arching. To alleviate this problem I have removed the battery and #6 AWG battery cables connecting the battery to the starter. while AC (alternating current) voltage can be transmitted along a relatively small cable without much voltage drop due to wire resistance, this is NOT true for DC (direct Current) which is what our batteries put out. Therefor it is imperative that with fairly long runs between the battery and starter as commonly seen in marine applications, the battery cables be sized properly. There are DC charts that will show the proper dia. cable depending on the length of the run and capacity to be transmitted. Check the internet. Since I was forced to deal with this issue now I decided to over size the cabeling for added insurance. I happened to have some red and black 2-0 high flex cable left over from a previous solar project, which was perfect for this application. To keep the voltage drop to an absolute minimum I opted to go with heavy duty coated copper POSTconnectors at the battery end. by using post connectors instead of the typical copper connectors for the threaded studs with wing nut, you get more mass and less potential for voltage drop at that point. I coated the wire with lithium grease before crimping the connector using a crimping tool used for making up new standing rigging for my sail boats. I then applied a thin coating of lithium grease to the outside of the connector and cable before heating the double wall shrink tubing to seal out moisture.
The battery was replaced with a multi purpose 27 series 1000 marine amp battery. FYI- CCA's are cold cranking amps which is rated at 0 degrees F. Marine amps is rated at 32 degrees F. You may think this is way overboard for such a small engine but diesels require a lot of torque to start easily and to have the torque you have to have plenty of capacity. So the whole exercise is to have the least amount of drop possible between the battery and starter. Paying close attention to battery capacity, correct cable sizing, and type of connectors used will do that. Oh, yes the job has resulted in the starter now being able to easily crank the engine with authority. The next step will be to replace the cracked plastic bleader screw on the top of the Racor filter. Apparently someone got a bit over zealous with torquing it in the past. I suspect I am having some air drawn into the fuel system causing part of the hard starting. I will keep you posted in hopes that this thread helps. Joe
The battery was replaced with a multi purpose 27 series 1000 marine amp battery. FYI- CCA's are cold cranking amps which is rated at 0 degrees F. Marine amps is rated at 32 degrees F. You may think this is way overboard for such a small engine but diesels require a lot of torque to start easily and to have the torque you have to have plenty of capacity. So the whole exercise is to have the least amount of drop possible between the battery and starter. Paying close attention to battery capacity, correct cable sizing, and type of connectors used will do that. Oh, yes the job has resulted in the starter now being able to easily crank the engine with authority. The next step will be to replace the cracked plastic bleader screw on the top of the Racor filter. Apparently someone got a bit over zealous with torquing it in the past. I suspect I am having some air drawn into the fuel system causing part of the hard starting. I will keep you posted in hopes that this thread helps. Joe