Spartans
Seaman
- Joined
- Oct 9, 2016
- Messages
- 56
All,
please bear with me here but I'm trying to understand the theory behind the power tilt trim differences running between different model years.... Mainly 1974 through 1990. All feedback welcome as there may be others here who would benefit (or can dispute my findings).
It seems that from about 74-77, OMC had two different types of PTT systems - one that had the lift plate, two cylinders with a single motor/reservoir - and another system (supplied only on larger outboards - 135 hp and up that had a single cylinder, motor and reservoir.
It looks like beginning in 1978, the lift plate system was dropped completely and the other, single cylinder system that was used on the larger pre-78 large hp engines were used on all outboards beginning in 1978 up until 1990. This is as far as I can tell since the manifold part number is the same for all years (1974-1990) and there was a change beginning in 1991.
I heard somewhere that early OMC products that did not get shipped with PTT and were ordered as a dealer option required this add-on product that mounted the cylinders and brackets external to the pivot assembly and clamp.
If I look up an engine - lets say a 1977 evinrude 70 hp, there is no PTT shown on the parts diagram but I know that motors of that era had PTT and it was the lift plate system.
Therefore, I guess my question is two fold:
1. I'm wondering that this lift plate system was an accessory or dealer add because if you wanted to install a newer post-77 PTT system on these outboards you would need to change out the clamp and pivot assembly and incorporate the PTT into the motor?
2. it seems that from parts diagrams that PTT units from 78-90 are all the same since all have the same manifold which fits between the transom brackets. So can these systems be used interchangeably?
Thanks
please bear with me here but I'm trying to understand the theory behind the power tilt trim differences running between different model years.... Mainly 1974 through 1990. All feedback welcome as there may be others here who would benefit (or can dispute my findings).
It seems that from about 74-77, OMC had two different types of PTT systems - one that had the lift plate, two cylinders with a single motor/reservoir - and another system (supplied only on larger outboards - 135 hp and up that had a single cylinder, motor and reservoir.
It looks like beginning in 1978, the lift plate system was dropped completely and the other, single cylinder system that was used on the larger pre-78 large hp engines were used on all outboards beginning in 1978 up until 1990. This is as far as I can tell since the manifold part number is the same for all years (1974-1990) and there was a change beginning in 1991.
I heard somewhere that early OMC products that did not get shipped with PTT and were ordered as a dealer option required this add-on product that mounted the cylinders and brackets external to the pivot assembly and clamp.
If I look up an engine - lets say a 1977 evinrude 70 hp, there is no PTT shown on the parts diagram but I know that motors of that era had PTT and it was the lift plate system.
Therefore, I guess my question is two fold:
1. I'm wondering that this lift plate system was an accessory or dealer add because if you wanted to install a newer post-77 PTT system on these outboards you would need to change out the clamp and pivot assembly and incorporate the PTT into the motor?
2. it seems that from parts diagrams that PTT units from 78-90 are all the same since all have the same manifold which fits between the transom brackets. So can these systems be used interchangeably?
Thanks