First off i need to know a good repair manual that i can buy so to be able to fix most problems on my own any suggestions?
Make (of engine): Mercruiser I/O
Model (of engine): Alpha
Hi my name isXXXXX will assist you.
Here is a link to Merc publications. click here
this site looks great any one of those you recomend over the other it looks like the 4 cylinder manual will work do you recommend any of the others? I have an older boat and had to put some tune up work into it but works great but there are some issues the gasket on the wter intake is leaking, the trim gauge does not work (they wanted 400 to fix it) there is a random nocking noise at high RPM and cold it seems to operate at a real high rpm then will drop down to normal and the steering is real loose is this normal. I know that is a lot and i appreciat your time and will accept your answers!!
That is the best manual for the money the other after market manuals are not as good. Leaking gaskets replace them. The trim gauge not working is usually the trim sender which is expensive to replace . You have to buy the trim sender and trim limit switches as a kit. As for the noise that will take some trouble shooting. There could be drive noise gimbal bearing, u-joint all to involved for a $4.50 question which is my portion of the money I receive. The engine running high rpms could be propping or a fuel starvation issue causing loss of rpms.
35 yrs. experience. I/O, Outboard & Inboard, Complete engine repairs.Certified Technician
On the nocking noise any chance it could have been related to drive oil being to low i added some and haven't heard it since but it was random anyway, the trim issue can it be fixed without terring into the motor?
Yes that can be an issue low gear lube. The trim sender is on the gimbal ring stbd side, check the wiring. To check the gauge is working ground the sender terminal on the gauge with key on the gauge should peg. If yes the gauge is good. That leaves the sending unit on the gimbal ring # X stbd side.
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great!!! and what about the loose steering there is a lot of slop on the engine side not the wheel, and as for the high rpm some say i may need a smaller/larger prop but that would't explain the dropping to a lower rpm would it?
The slop is in the drive itself. If you have someone hold the steering wheel while you move the drive from side to side you will see where the play is. The full throttle rpms for that engine are 4400-4800 if you are over 4800 you need more pitch. The loss of rpms is possibly a fuel restriction in the fuel filter or the boat side fuel system. There are 2 filters on the engine,one in the carb at fuel fitting and one in the fuel pump. If these are clean then run the engine on another fuel source if the engine runs better then the boat side fuel system is dirty.
ya its running closer to 5000-5500 regularly and at first it jumps to closer to 6000 but will drop back down to 5000 or below and i had a hole carb rebiuld already as weel as replacing both those filters have just started using a fuel additive, any recomendations on fuel? i know regular fuel is not good for the engine hints the fuel additive.
Regular fuel is fine just try to stay away from ethanol enriched fuels. You need to add allot of pitch to your prop. 1" of pitch per 100 rpms
what do you mean by pitch? I have three different props for the boat the one thats on there is a nice one stainless steel but is smaller then the other two, maybe a new prop?
The prop has 2 dimensions one is diameter the other is pitch which is the number of inches in the angle of the prop blades which in theory push the boat so many inches forward in one revolution. That boat should be running something like a 19 or 21" pitch prop.
how do i measure my prop to make sure it is the right size? and thank you for all your help it has been huge!!! this is my last question.
The props should be marked on the side or where the hub of the prop. You can't measure the prop pitch as this takes special pitch blocks to measure. You can take your props to a prop shop for sizing.